Hi Ahmed
Some time ago I asked the same question. My conclusion was:
+ Set the error as a warning is not possible, because the error is harcoded >>> 'message id 'K/' type 'E' number 832' after the function COPA_UPDATE_STANDARD_MEASURES.
+ There is no customizing to exclude some materials, the standard uom work for all.
I found 2 Options:
1. Create 1-1 conversion in material master (marm) for all the materials that dont have conversion to the standard uom. (I dont like this solution)
2. Desactivate the standard uom customizing. Create your oun code to fill the field with exit COPA0002 Enhancement for valuation in Profitability Analysis (This is the solution that i use).
Arturo.