E_INVALIDARG????? ARGHHHHHH!!!!

Please help, Blt returns E_INVALIDARG hRet = Screen::getBackSurface()->Blt(&rc2, g_pSurface,&rcRect,flag,NULL); It is working perfectly for some images, and then does this stupid thing for some ones else.. the rectangles and the flag have no problem whatsoever... so, the problem must be witht the surface. is there a method to read the properties of the surface to know what is wrong? Thank you very much in advance.. *sob* *sob*