hey all, i just had the exact same problem with limewire. I used ottermans approach and it worked perfectly.

if you dont want to go through all of that then just check your application data folder. if it doesn't contain the limewire folder then thats why your having this problem. for some reason my limewire application data folder had moved itself to the same for that the application data folder was in, and renamed itself .limewire . i recreated the problem just to ensure that was the cause, and behold i couldn't download. Then i just copied the folder, renamed it LimeWire and placed it in the application data folder, and limewire worked properly again.