I tried to help this person in the IRC spanish channel....here's some things he told me and missed in his message....
He didn't had any plugin installed, and when he unistalled Plus, the messenger worked fine...he told me that he tried reinstalled plus, but with the same results...
he mentioned that he can start his session (log in), but when he tried to open a chat window thats when the problem happen...
PS... Im just as surprised as you that Im posting in the Help & Support forum...