Open limewire and on the tool bar at the top click, Help > About LimeWire, And a window will open that'll show what version of limewire and java your using.
Turn the xp firewall off and make sure you have allowed LW access to the internet through your norton firewall.
To turn off the windows xp firewall, from you desktop go to Start>Control Panel>Security Center>Windows firewall> tick the off button then click ok. It will warn you not to turn it off but if you have norton running then it's ok.
Instructions to configure Norton here:
Configuring firewall rules for Web-enabled programs
To check for any other java versions, from you desktop go to Start>Control Panel>Add or Remove Programs, and see if more than one is listed.