Plotting Problems

I try to plot the following structure:
dat=mpheval(out,'solid.E','dataset','dset1')
dat =
expr: {'solid.E'}
d1: [1x8856 double]
p: [2x8856 double]
t: [3x17334 int32]
ve: [8856x1 int32]
unit: {'Pa'}
But, when I used the command mphplot(dat) I obtain the following error:
>> mphplot(dat)
??? Error: File: mphplot.p Line: 2063 Column: 0
Expression or statement is incomplete or incorrect.

I appreciate any help I could get
Diego Fernandino