Copying files to the computer

I'm having a problem copying the pics from the camera to the computer. Windows XP recognizes the camera and I can select the pics I want to copy. but when it starts to copy, I always get an error message saying its impossible to copy the current image and I have options to retry, ignore pic, ignore all, or cancel. If I retry or ignore, the same thing happens, and I end up cancelling. After this, I dismount the camera and it stays frozen, until now the only thing that works is taking out the battery and replacing it. I do not think it is the camera because we have successfully copied the pics onto a macintosh. Any suggestions would be most appreciated. Thx
Mark
no pic