postgres 7.0.3 hangs

Hi,

Is there any known problem with postgres 7.0.3 on a linux box (2.4 kernel)
hanging?  I noticed it from time to time in the past, but it was
infrequent enough that I didn't do anything about it, but its become a
much more pervasive problem.  I have multiple threads runing and one of
them hangs on an INSERT (visible in the process listing).  When I check
the process status, it is sleeping.  Other threads, presumably trying to
access a locked resource also hang (though they are otherwise response,
you can do other things so long as you don't access whatever resource is
locked).  Even if a I kill the sleeping process, the next one that comes
in place after it (presumably waiting on that lock) blocks in the same
way.  I have to restart the whole database to get things to work again.
I know this is not a very detailed analysis, but has anyone seen anything
like it before?  Is upgrading postgres likeley to solve the problem?

Thanks,
Sheer