Dead Lock problem with 8.1.3

Hi Folks,

I have a strange Problem (to be honest there are more than one, but this
is one of it) after Upgrading to Postgres 8.1.3. The following SQL seems
to produce a deadlock while doing an endless reading of a temp table:

SELECT s.sid FROM stud s, stud_vera v WHERE s.sid = v.sid AND v.veraid =
34 AND s.sid NOT IN ( SELECT sid FROM stud_vera WHERE veraid = 2 );

It should give me a List of sids which are connected to veraid 34 but
not to veraid 2 at the same time. When removing the 'AND v.veraid = 34':

SELECT s.sid FROM stud s, stud_vera v WHERE s.sid = v.sid AND s.sid NOT
IN ( SELECT sid FROM stud_vera WHERE veraid = 2 );

everything works really fine (even if I include an additional criteria
like 'AND stud_vera.status > 0' ). On Postgres 8.0.8 this problem
doesn't exist. The first clause works with a lot of additional criteria
very fast.

Any Idea?

*greets*
Kai