That wouldn't be the problem as that padlock notice you see at the top of your searches is to notify you of a particular search result that contains a virus...
It's a 75.7 KB .exe & shows up as "Urgent LW update - download & install now". If people download that thing they could end up infected. To try to prevent careless people from downloading a dangerous file, the warning banner was added to LW's interface.
The padlock symbol doesn't apply to music or video etc, only to LW updates...
Try deleting your preference folder/s...This will reset your configurations back to default and get rid of any corruption that may of happened...
Fixes for Limewire when LW isn't operating as it should LimeWire Pref Folder in Vista
If that doesn't help...
Go to Tools > Options > Searching > Lisence Warning and make sure the box
is not ticked and select apply...
If that does not help try going to your Connections Tab in limewire, if it's not showing up go to Veiw > Show/Hide and make sure the connection tab has a tick next to it...
Then click on the Hosts and remove them and let Limewire search for some more...
(try to take note of the hosts IP numbers if the same ones keep re-appearing add them to your host filter...)
Tools > Options > Filters and select the Host Filter and add these IP's into it and select apply...
Try installing PeerGuardian, it will help keep the fake hosts out...Remember to enable PG just before you start limewire up...
Phoenix Labs » PeerGuardian 2 If you're using Vista, there's this PG2 Beta available for Vista users. PeerGuadian 2 for Windows Vista beta released - Phoenix Labs PeerGuardian 2:Manual - Phoenix Labs Wiki
Another thing if you are using limewire 4.13 and later you can apply this hostile list...This will block known fake IP addresses...
The TechNutopia Fullsize Hostiles List for BearShare and LimeWire