The error in question is simply one of many that i can spot from this change. It had the unfortunate side-effect of breaking this addon. I rewrote ProfessionTabs to be more robust when 5.0 hit, especially so since I am no longer playing. It seems like CombuctorProfTabs is completely incompatible with the latest version of ProfessionTabs. Added support for AdvancedTradeSkillWindow and Skillet Fixed the tab update problem with tradeskill based addons Small rewrite in preparation for Cataclysm Updated to support the latest version of MrTrader Tabs are now only updated when profession information changes The GetProfessions and GetProfessionInfo APIs are now used rather than the IsSpellKnown API to obtain profession information Some code optimizations have been added Tab selection accuracy has been improved The toc file has been updated for patch 5.0.4 Fixed issue with detecting profession ranks for races with profession skill bonuses

This is an unavoidable restriction set in place by Blizzard for addons which use secure code. ProfessionTabs cannot add or remove professions while in combat, but it will update this information once combat ends. It also supports multiple tradeskill based addons: ProfessionTabs supports creating tabs for: Tabs will update automatically whenever your professions change. It will add tabs of your professions to your tradeskill and trade frames. ProfessionTabs is an addon inspired by TradeTabs. Note: I highly recommend deleting the old ProfessionTabs folder if you're updating from an older version.

How do you change professions in wow