Webex problems with firefox in linux

When trying to connect to a webex meeting from my linux machine, we had this "Locking assertion failure" problem. The exception was something like

Locking assertion failure.  Backtrace:
#0 /usr/lib/libxcb-xlib.so.0 [0xb7cca767]
#1 /usr/lib/libxcb-xlib.so.0(xcb_xlib_unlock+0x31) [0xb7cca8b1]
#2 /usr/lib/libX11.so.6(_XReply+0xfd) [0xab708a8d]
#3 /opt/java/jre/lib/i386/xawt/libmawt.so [0xab81864e]

Upon trying multiple solutions on web, we finally fixed it by installing compat-libstdc++-33 rpm.