Andrew,
Sorry, I didn't answer your question properly (I'm too sleepy). I've only verified that patching v2.6 with Jeff's fix makes Schema Browser work.
Where does the official oracle driver live? The
AOLServer SourceForge Page shows version 2.6. I checked out the
CVS version, and it does not seem to have the fix (and Schema Browser still throws the error).
acs-misc.sourceforge.net doesn't have a link to any version of the oracle driver.
The canonical source for oracle and postgres drivers is
aolserver.com.
I applied and committed that change.
I have used a version of the driver with that change for some
time with no apparent problems (although it should be pointed
out that other than munging around in the data dictionary
LONGs are not used in openacs, so that's not that telling).