problem defining variable function to obtain strain value

Hi, currently i am trying to calculating strain by using this formula in structural mechanics module 4.0 comsol. I am not able to get the strain value. The only value i get is the intop1(1) but comsol cannot identify other variables sch as intop1(intcpl_source_S1). Any ideas? I've attached the variables that i've used below.

Deform formula:
sqrt((t1x+uTx*t1x+uTy*t1y+uTz*t1z)^2+(t1y+vTx*t1x+vTy*t1y+vTz*t1z)^2+(t1z+wTx*t1x+wTy*t1y+wTz*t1z)^2)

Thank u..