java.lang.RuntimeException: Expression is not consistent with previous one

Hello,

I am new at comsol and at the moment am having trouble generating solver sequences from a study in a RF module of Comsol 4.0.
I have defined a simple geometry which can be varied by Parameters defined in the Global definitions.

When generating solver sequences it gives an error: "Expression is not consistent with previous one"

Mesh_element_size [com.comsol.util]
00007:252 INFO ServiceEvent REGISTERED [org.eclipse.core.contenttype]
00007:256 INFO BundleEvent STARTED [org.eclipse.core.contenttype]
00007:441 ERROR Unhandled error occurred during event processing. [com.comsol.gui]
java.lang.RuntimeException: Expression is not consistent with previous one
at com.comsol.model.applapi.VariableInfo.merge(Unknown Source)
at com.comsol.applapi.variables.h.a(Unknown Source)
at com.comsol.applapi.variables.l.a(Unknown Source)
at com.comsol.applapi.variables.l.a(Unknown Source)
at com.comsol.applapi.variables.l.addScalarVariable(Unknown Source)
at com.comsol.applapi.util.m.a(Unknown Source)
at com.comsol.applapi.variables.l.resetAllVariables(Unknown Source)

The "h" and "l" ar the height and width parameters, which are used for defining geometry, e.g., size of a rectangular object.
Has anyone encountered similar problem and found a solution for it?

Edgars