thres solutions were given. if you do a material analysis then it will ask you (if its the first time) for densities for each component thus giving you the units as it asks you for the values.
second, go into mechanica and it might give diferent units error.. have not tried it but might work.
third is this map key that you can get working too. "Otherwise, you can create a mapkey to run through a series of Model Info | Part commands to select each component. If you do a Sel By Menu command, you can autofill in the component selected from a BOM of your assembly. Depending on how you have your info windows set up confi-wise, you can just review these files (i.e., do a text search through the files saved to disk to sort)."
thanks to Caleb Coburn for first and third and Bower David for second. I list time in order of difficulty from my perspective. using the first I was able to identify all my bad components and bring them back to the same units... exept for one wich cannot be changed unfortunatelly, but at least I know who the bugger is.