Get this when clinking on the Jewel crafting icon above level bar in the upper right of trade skill window.

<Version: 4.36)>

1x [ADDON_ACTION_FORBIDDEN] AddOn 'Skillet' tried to call the protected function 'UNKNOWN()'.
[string "@!BugGrabber\BugGrabber.lua"]:519: in function <!BugGrabber\BugGrabber.lua:519>
[string "=[C]"]: ?
[string "=[C]"]: in function CastSpellByName' [string "@Skillet\Skillet-4.36.lua"]:1285: in function ChangeTradeSkill'
[string "@Skillet\Skillet-4.36.lua"]:1337: in function SetTradeSkill' [string "@Skillet\UI\MainFrame.lua"]:621: in function TradeButton_OnClick'
[string ":OnClick"]:2: in function <[string ":OnClick"]:1>

I suspect that you have a corrupted install of Skillet or a major conflict with another addon.

Please download Skillet-4.36 from here, verify the MD5 checksum, manually install it, and try again.

If it still fails, please disable all other addons and try one more time.

If it still fails, then I'll need you to enable Skillet debugging, create a single failure, and then upload the data for me to analyze. I'll give further instructions if we get to this point.

The tradeskill button within the Skillet frame is failing for me as well but closing Skillet and opening JC with an action button works.

Fixed

Please see issue #1. If you logout and login again (without closing WoW.exe), this Blizzard bug won't bother you (until the next time).