For some reason, there is an error that says: " an unknown error occured while opening your file"

The file is on a USB. Is there any way to fix it? I do have a back up, but it is about 100 frames from where I am now, and what I did was something somewhat difficult. Help!

Try to put it on the desktop?? =D

I did, and it still said the same thing. I did disk cleanup and disk defragmenter, but with no avail. Is there an expert on computers here? Does the creator/upgrader of the program come here? If not, where can I find him/her? I should probably ask them.