After successfully running Maxima on XP., it 'suddenly' started failing.
I tracked the problem down to the fact that I had Norton's AV + firewall, which I UNINSTALLED (after much sweating of blood as it is a pain to remove). It left some entries with regard to firewall which prevented Maxima socket(?) communications.
I eventuallly purged everything regarding Norton's from directories and REGISTRY (look for any refs to Norton, Symantec, NOD etc).
I then reinstalled and ALL is OK.
note I run Zone alarm (free) version for firewall.
I Installed 5.13 on XP prof with Zone alarm a few days ago...NO PROBLEMS works OK, using wxmaxima , event plotting works OK
Hope this helps.