We had to switch from UTF8 back to Western European (WE8ISO8859P1).

It's a packaged app, so we couldn't figure out what they were doing.

Come to think of it, we did have a problem with JDBC drivers and Thai character convertion. We upgraded the JDBC drivers to match the db version and that fixed it. (9.2.0.4)

Other than that, I don't know of any other character set conversion issues, but better check MetaLink for bugs on your specific version.

Best of luck, I'd be curious to know it goes.