Pardon me for putting the most obvious answer first:
Upgrade! You're way behind the curve and can't rely that there's any
other update or even security fix. Hopefully you have at least
deployed the last
available patch.
Second option, as a fix until you upgrade: You'll need to figure out
the context in which this exception occurs. I've seen it before (but
there's no guarantee that it's the same context). Searching with that
context might reveal something for you. But with just the error
message and no context, there's no way to provide good clues.
