What steps will reproduce the problem?
1. Join a party (either when in combat or out of it).

What is the expected output? What do you see instead?

Party frames should appear, no errors. Instead, an error is thrown up and the Warrior in the party (who was invited after I joined the party) doesn't have its normal unit frame. Instead, the entire frame for that party character is a big "yellow bar". No health, no text, no portraits.

I left the party & rejoined, no change. The error didn't reoccur, but the Warrior was still a big "yellow bar".

What version of the product are you using?

r677

Do you have an error log of what happened?

ag_Extras-09-19-07\\modules\\castbar\\castbar.lua:206 aUFFontString369:SetText(): Font not set\nag_Extras-09-19-07\\modules\\castbar\\castbar.lua:206 in function `func'\nag_UnitFrames-2008-08-06\\ag_UnitClass.lua:187 in function <Interface\\AddOns\\ag_UnitFrames\\ag_UnitClass.lua:182

Please provide any additional information below.

r677 is completely unusable due to this issue. Yes, the flickering auras on the target of target frame were bothersome. But this fix for that issue is far worse.

Revert back to r676 and the party bars go back to normal with no issues on any party joined. The target of target frame has fickering auras again with r676. But its by far the lesser of two evils.