Crash of Postgresql on Windows

Hello,

I am sending this email since I am hitting a snag with postgresql. I
am currently running the following version of postgresql:
Postgresql 8.3.5 on Windows XP Pro 32bits

I am getting a crash whenever I try to perform an update on some rows.
More precisely, I have recently imported a dataset and managed to work
through it easily. However, when performing one update I am getting
the following error:

GMT PANIC:  could not write to log file 40, segment 44 at offset
8929280, length 1744896: Invalid argument
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
2009-02-04 12:02:34 GMT LOG:  WAL writer process (PID 2916) exited
with exit code 3
2009-02-04 12:02:34 GMT LOG:  terminating any other active server processes
2009-02-04 12:02:34 GMT WARNING:  terminating connection because of
crash of another server process
2009-02-04 12:02:34 GMT DETAIL:  The postmaster has commanded this
server process to roll back the current transaction and exit, because
another server process exited abnormally and possibly corrupted shared
memory.
2009-02-04 12:02:34 GMT HINT:  In a moment you should be able to
reconnect to the database and repeat your command.
2009-02-04 12:02:34 GMT WARNING:  terminating connection because of
crash of another server process
2009-02-04 12:02:34 GMT DETAIL:  The postmaster has commanded this
server process to roll back the current transaction and exit, because
another server process exited abnormally and possibly corrupted shared
memory.
2009-02-04 12:02:34 GMT HINT:  In a moment you should be able to
reconnect to the database and repeat your command.
2009-02-04 12:02:34 GMT WARNING:  terminating connection because of
crash of another server process
2009-02-04 12:02:34 GMT DETAIL:  The postmaster has commanded this
server process to roll back the current transaction and exit, because
another server process exited abnormally and possibly corrupted shared
memory.
2009-02-04 12:02:34 GMT HINT:  In a moment you should be able to
reconnect to the database and repeat your command.
2009-02-04 12:02:34 GMT LOG:  all server processes terminated; reinitializing
2009-02-04 12:02:35 GMT FATAL:  pre-existing shared memory block is still in use
2009-02-04 12:02:35 GMT HINT:  Check if there are any old server
processes still running, and terminate them.

I am a bit lost on what to do next. I have tried running the query
several times even changing the parameters to make sure if it wasn't
something in the sql.
UPDATE gtable AS g
       SET     code = '00' -- 04
       WHERE   g.code = '04'
               AND g.cc = 'TW';

UPDATE gtable AS g
       SET     code = '00' -- 04
       WHERE   g.d IN (6724652, 1673813);

Those two queries do exactly the same thing but they both crash with
the same information, except for the length between the two queries.
What should I do?

Emilie Laffray