Symantec Intrusion Protection 11.359 - 4 prevents firefox process from stopping

I am having a problem with Firefox 17.0.5.  When I close Firefox the Firefox.exe process does not end.  I norowed it down to the Symantec Intrusion Protection 11.359 - 4 plug in by disableing all prigins and enableling one at a time.  I now have all the other pligins enabled and do not have a problem.  This problem onlu happens in Firefox.  What do I need to do to solve the problem?

Thanks