Calibration of material or Material PRT

Dear Friends,

Here i have got an issue in my implementation

I want to do regular calibration of Material using maintenance plan

So i have to get an calibration order and Inspection lot for the material when i schedule the maintenance plan

but when i schedule the maintenance plan iam getting the "no inspection lot is generated".

I want to know what is the problem

Pleas help me

Ur reply is highly appreciated

with regards,

V.Vijay Kumar