I also had this problem. I run windows XP and found that all was OK with myself (Being Administrator) but other accounts could not download (100% complete immediately and 'Could not move to Library '). I have however now fixed this.

The problem is that the default download folder is in the Limewire folder which in turn comes under folder 'Program Files'. Only the administrator has access to this folder.

Solution: in Limewire options set the SAVED folder to a shared folder that all users have access to. I did find though that using the browse option did not work so I had to manually type in the path and apply. This worked for me.