Exception thrown with Livelink Model - Can anyone help?

I am getting the following exception with my LiveLink model with MATLAB but I can't figure out why. Help would be very much appreciated. I have attached the file.

??? Java exception occurred:
Exception:
com.comsol.nativejni.FlNativeException: Failed to evaluate expression
(rethrown as com.comsol.util.exceptions.FlException)
(rethrown as com.comsol.util.exceptions.FlException)
Messages:
The following feature has encountered a problem

The following feature has encountered a problem

Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Domain: 1 3

Failed to evaluate expression
- Expression: mod1.slpf.mu

Failed to evaluate operator
- Operator: mean
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression: mean(mod1.slpf.mu)

Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression:
d(((mod1.u+mod1.slpf.Ls*(mod1.slpf.lm_ntaux-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.nx)/mod1.slpf.mu-mod1.slpf.ubtcx)*test(mod1.slpf.lm_ntaux)+(mod1.v+mod1.slpf.Ls*(mod1.slpf.lm_ntauy-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.ny)/mod1.slpf.mu-mod1.slpf.ubtcy)*test(mod1.slpf.lm_ntauy))*(dvol),{test@27})
- Feature: Stationary Solver 1 (sol1/s1)
- Error: Failed to evaluate expression.

Stack trace:
at evaltree.cpp, row 708, ()
at xevaluators.cpp, row 364, ()
at xevaluators.cpp, row 1092, ()
at xoperator.cpp, row 418, ()
at evaltree.cpp, row 708, ()
at xevaluators.cpp, row 364, ()
at com.comsol.solver.SolverOperation.addError(Unknown Source)
at com.comsol.solver.SolverOperation.execute(Unknown Source)
at com.comsol.model.internal.impl.SolverSequenceImpl.a(Unknown Source)
at com.comsol.model.internal.impl.SolverSequenceImpl.h(Unknown Source)
at com.comsol.model.internal.impl.SolverSequenceImpl.runAll(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.comsol.clientserver.impl.JobImpl.run(Unknown Source)
at com.comsol.server.internal.c.a(Unknown Source)
at com.comsol.server.internal.c.a(Unknown Source)
at com.comsol.server.internal.c$c.a(Unknown Source)
at com.comsol.server.internal.c$c.a(Unknown Source)
at com.comsol.server.internal.c$c$1.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: Exception:
com.comsol.nativejni.FlNativeException: Failed to evaluate expression
Messages:
Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Domain: 1 3

Failed to evaluate expression
- Expression: mod1.slpf.mu

Failed to evaluate operator
- Operator: mean
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression: mean(mod1.slpf.mu)

Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression:
d(((mod1.u+mod1.slpf.Ls*(mod1.slpf.lm_ntaux-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.nx)/mod1.slpf.mu-mod1.slpf.ubtcx)*test(mod1.slpf.lm_ntaux)+(mod1.v+mod1.slpf.Ls*(mod1.slpf.lm_ntauy-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.ny)/mod1.slpf.mu-mod1.slpf.ubtcy)*test(mod1.slpf.lm_ntauy))*(dvol),{test@27})

at com.comsol.nativejni.solver.FlSolver.femStatic(Native Method)
at com.comsol.nativejni.solver.FlSolver.femStatic(Unknown Source)
at com.comsol.nativemph.c.i.g(Unknown Source)
at com.comsol.nativeutil.runnable.f.run(Unknown Source)
at com.comsol.solver.solution.SolverBase.a(Unknown Source)
at com.comsol.solver.solution.SolverBase.doExecute(Unknown Source)
... 17 more

at com.comsol.model.clientserver.ClientManagerImpl.a(Unknown Source)
at com.comsol.model.clientserver.ClientManagerImpl.runServerJob(Unknown Source)
at com.comsol.model.internal.impl.SolverSequenceImpl.runAll(Unknown Source)
at com.comsol.model.internal.impl.StudyImpl.d(Unknown Source)
at com.comsol.model.internal.impl.StudyImpl.c(Unknown Source)
at com.comsol.model.internal.impl.StudyImpl.a(Unknown Source)
at com.comsol.model.internal.impl.StudyImpl$1.a(Unknown Source)
at com.comsol.model.internal.impl.StudyImpl$1.execute(Unknown Source)
at com.comsol.model.clientserver.ClientManagerImpl$1.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: Exception:
com.comsol.nativejni.FlNativeException: Failed to evaluate expression
(rethrown as com.comsol.util.exceptions.FlException)
Messages:
The following feature has encountered a problem

Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Domain: 1 3

Failed to evaluate expression
- Expression: mod1.slpf.mu

Failed to evaluate operator
- Operator: mean
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression: mean(mod1.slpf.mu)

Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression:
d(((mod1.u+mod1.slpf.Ls*(mod1.slpf.lm_ntaux-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.nx)/mod1.slpf.mu-mod1.slpf.ubtcx)*test(mod1.slpf.lm_ntaux)+(mod1.v+mod1.slpf.Ls*(mod1.slpf.lm_ntauy-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.ny)/mod1.slpf.mu-mod1.slpf.ubtcy)*test(mod1.slpf.lm_ntauy))*(dvol),{test@27})
- Feature: Stationary Solver 1 (sol1/s1)
- Error: Failed to evaluate expression.

at com.comsol.solver.SolverOperation.addError(Unknown Source)
at com.comsol.solver.SolverOperation.execute(Unknown Source)
at com.comsol.model.internal.impl.SolverSequenceImpl.a(Unknown Source)
at com.comsol.model.internal.impl.SolverSequenceImpl.h(Unknown Source)
at com.comsol.model.internal.impl.SolverSequenceImpl.runAll(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.comsol.clientserver.impl.JobImpl.run(Unknown Source)
at com.comsol.server.internal.c.a(Unknown Source)
at com.comsol.server.internal.c.a(Unknown Source)
at com.comsol.server.internal.c$c.a(Unknown Source)
at com.comsol.server.internal.c$c.a(Unknown Source)
at com.comsol.server.internal.c$c$1.run(Unknown Source)
... 3 more
Caused by: Exception:
com.comsol.nativejni.FlNativeException: Failed to evaluate expression
Messages:
Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Domain: 1 3

Failed to evaluate expression
- Expression: mod1.slpf.mu

Failed to evaluate operator
- Operator: mean
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression: mean(mod1.slpf.mu)

Failed to evaluate variable
- Variable: mod1.slpf.mu
- Geometry: 1
- Boundary: 8 9 10 11 20 22

Failed to evaluate expression
- Expression:
d(((mod1.u+mod1.slpf.Ls*(mod1.slpf.lm_ntaux-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.nx)/mod1.slpf.mu-mod1.slpf.ubtcx)*test(mod1.slpf.lm_ntaux)+(mod1.v+mod1.slpf.Ls*(mod1.slpf.lm_ntauy-(mod1.slpf.nx*mod1.slpf.lm_ntaux+mod1.slpf.ny*mod1.slpf.lm_ntauy)*mod1.slpf.ny)/mod1.slpf.mu-mod1.slpf.ubtcy)*test(mod1.slpf.lm_ntauy))*(dvol),{test@27})

at com.comsol.nativejni.solver.FlSolver.femStatic(Native Method)
at com.comsol.nativejni.solver.FlSolver.femStatic(Unknown Source)
at com.comsol.nativemph.c.i.g(Unknown Source)
at com.comsol.nativeutil.runnable.f.run(Unknown Source)
at com.comsol.solver.solution.SolverBase.a(Unknown Source)
at com.comsol.solver.solution.SolverBase.doExecute(Unknown Source)
... 17 more

Error in ==> ModBenchmark at 379
std1.run