Nice catch Hobo (sorry I missed that). Deleting the prefs folder (use spotlight to search in the Home folder to find it) shouldn't matter if the LW did indeed come from the official LimeWire site, but it can't hurt. Then redownload the Basic (free) one from the official site at
http://www.limewire.com/english/content/download.shtml and reinstall.
Were you able to plug your friend's internet cable into your Mac, Flores? Once your new LW is installed, the key settings to compare will be in the Advanced->Firewall section of the LimeWire options. Just use the same settings as your friends, since they have pretty much the same options.
Other than that, the other settings shouldn't matter, since you probably have your Apple Menu->Location->Network Preferences set to "Automatic"