Like many others I have recently experienced this problem as well. I searched the forum and found many proposed solutions but nothing that fixed the problem. So I decided that since limewire couldnt move the file to the library, maybe something was wrong with the "incomplete" folder. Sure enough when i opened the folder there were approximately 13,000 files of similar name and type. I proceeded to delete the entire incomplete folder and then created a new folder and named it "Incomplete". This solved the problem for me.

Hopefully this will work for others.

I apologize if this solution had been posted elsewhere, I didnt come across it in my search of the messageboard.