Hello,

The cause of the incompatibility between recent OA releases (>= 0.8.5) has been discovered and should be fixed in the next release (or maybe sooner in a hotfix).

Meanwhile, I have made a compatibilityfix.pk3 that you can offer to your client to autodownload. It's very small, but necessary, and is currently the only way to make ExcessivePlus works as a server-side mod while using OpenArena v0.8.8 assets.

You can find all the instructions here:

http://openarena.ws/board/index.php?topic=4514.msg44138#msg44138