Renaming Raw files with Photoshop CS

[Bsmooth]

This will probably sound stupid,but... I can't seem to rename my Raw images from my 20D in Photoshop CS. I tried batch renaming and this is what I used the date followed by the ext.:3-15-05BlkLeaves using extension .CR2.I have rename in same folder and start with Serial number 1.I keep getting this same message:You must include at least one of the document names,serial number or serial letter choices so the destination name is different for different input files. What does that all mean?
More to the point how do I do the renaming.I thought a date with description followed by the .cr2 extension should work fine.

[toddb]

When doing batch reanaming, PS has to have something to increament for the next name (or like is says us part of the original name which all should be uniqe already)...or you would end up with the same name for all you photos which the OS would not allow.