problem after reading restart file

Hello,

I have met a problem by using restart. i have three related files. First one is for generating particles using "insert/pack", the second one is for making all paritlces settled in a box, the thrid one is for moving mesh box using "fix move/mesh" as follows:

"fix shear1 all move/mesh mesh top linear 0.005 0 0"

however I got following error message:

"ERROR: Illegal fix move/mesh command, illegal mesh ID provided (fix_move_mesh.cpp:63)"

acutally, i defined the mesh "box" in all three files using "fix mesh/surface/stress".

I don't know what's wrong with my files. Could anyone help me with it?

By the way, in my simulation Liggghts 2.1.1 was used.

thanks,

Xuetao