Torrents stopped downloading...?

[JuliaJolie]

I've had Limewire for a few years, but I recently tried to install uTorrent. I had to uninstall uTorrent because I couldn't map the ports myself (internet is in roommate's name, and he couldn't remember his IP username and password, and has now scarpered). I stupidly tried the same thing with BitTorrent, and found the same problem (I am a n00b, didn't realise BT would also need manual port mapping).

Before my torrents were automatically opening in Limewire, but now all of a sudden after installing and uninstalling UT & BT the torrents in LW are giving me 3 errors: either "file is malformed" or "file does not exist" or "waiting 300s for sources". It can't be that these are fake files - I'm getting them from the same sites as I've downloaded previous torrents from.

Any ideas as to what's been going on? I changed the default program back to Limewire, but it's still not working. Even the torrent icon is just a blank white square (lol, the technical term) and not the green downwards-pointing arrow I've been used to the past few months of LW torrent downloading.

I'm aware it would be way easier to just go for UT or BT, but it isn't an option right now, as the roommate has gone AWOL and everything is in his name, and I'm in the middle of a massive torrent dl that I don't want to get messed up if I have to reinstall LW...