Yeah, looks like some bad/premature XML merging was to blame...
There is now an hotfix available (v1.08.037) that will fix these issues, along with:
+ always-missing bows
+ cur-mana values not being correct post battle
Note that previous saved games will still have the 'always-miss' bow issue, but the ability crashes will be gone. Also, if you have the private MP build, you will have to uninstall and reinstall to see the newest build. We will have a new MP build up on Monday with these changes.