the older Free installers are here
http://www3.limewire.com/download/
http://www9.limewire.com:82/download/

I don't think you can get an older Pro--but you are entitled to Pro Support
http://www.limewire.com/english/content/proform.shtml

btw--the new Pro (3.6.10 or .11) is supposed to work around many of the connection problems (many were caused by home routers not handling the many connection attempts LW needs to get connected). Have you checked your home router's firmware reports? Some Linksys routers, for example, worked best when the AOL parental features were turned off, or if the firmware was reverted to an earlier version. USB routers were also causing troubles too. Maybe if you posted your OS and connection details someone might recognize your setup.

The best way to determine if the problem is in LW or your router is to try connecting one of your machines directly to the cablemodem. That at least will show you if it's the router.