LimeWire does some intelligent guessing before returning results for files. If it thinks that the other side isn't going to be able to upload anything (which is the case if both sides are firewalled) then it won't return any results. It also doesn't return any results if the uploads are keeping the client busy (because anyone trying to download at that point in time would just get a busy response). In order to effectively test, you need to make sure that both machines can accept incoming connections.

Regarding the startup issues -- are you using the Windows (English) installer?

Configuration files are stored under C:\Documents And Settings\<your username>\.limewire . This means that you can install one version of LimeWire on the machine, but multiple people can have different configurations. It also means that after uninstalling, the config files will remain (which is the way most programs nowadays work). You can safely delete this directory and LimeWire will revert to the 'factory defaults'. We're considering adding a button that will automatically restore all settings to their defaults.