strange font lock (for latex) behavior in emacs

[HS]

First of all, my apologies for the cross postings, but I figured the 
problem could be solved by anyone in all these groups.

It is to do with font lock in emacs for Latex.

I have Auctex installed (ver 10.0g, release 4) with emacs (ver. 21.2 
release 18) on Redhat Linux 8.0 (kernal 2.4.18-14). When I open a .tex 
document, the font lock mode behaves in a strange way. Many commands are 
not highlighted at all (\documentclass, \maketitle, \item, {they are 
supposed to be highlighted I guess} etc). And sometimes, when I begin 
typing "\usepackage....", the usepackage command starts oft highlighted 
(in pink) but midway turns into normal text (black on white).

Moreover, I have also seen some highlights actually flash on and off at 
random interval!

Font-lock works perfectly in CC mode.

Quite honestly, at present I am not even sure where to start to look for 
a solution. So your comments are most welcome and all help is very much 
apprecaited.

Thanks,
->HS
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