[AUCTeX] error entering $

[Jim Burton]

I am using version 11.83-4 via the ubuntu Feisty package on emacs 21.4.1 and
*sometimes* when I try to enter a $ I get an error:

Wrong number of arguments: #<subr set-match-data>,2

I get the same error using C-C C-f C-e to emphasise text (whether or not there
is a selected region), but like I say, this might not happen the next time I
work on the same file...is this something I can fix or should I stop using the
deb and install the latest version?

Thanks,

Jim