Arjun,
It happens on my side whenever I post anything to a forum. The proc
forums::message::new has a 'posting_date ""' parameter which passes
an empty string to Oracle. I'm not an Oracle guru but I presume it
sees that it has a parameter, albeit empty, thus not assigning the
default sysdate to it. Then when the insert happens, it fails
because posting_date is not nullable. That's why I came up with the
above temporary fix. I'm using Oracle 8.1.7 and the 2.6 oracle
driver from the old arsdigita aolserver distribution if in case it's
an Oracle issue. And I get this on two different servers connecting
to two different Oracle dbs.