I use this addon as well, seems theres a fix. Quoting from curse:
Since this is such an important addon to many of us, I am bumping this to the top with proper respect given. This works to make RPB work under 3.2 and was originally posted by Verik:
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This is how I fixed the error I was getting.
1. Go to the RoguePowerBars folder and open RoguePowerBars_Buffs.lua in a text editor.
2. Scroll down to the line that says -- Troll racial
3. Go down three lines to "SpellID = 20554," and change 20554 to 26297
4. Save and test if it's fixed the next time you load your UI.
That block of text should look like the following after you are finished:
-- Troll racial
RoguePowerBar_Buff_Default[GetNext()] = {
StatusBarColor = { r = 0.9, g = 0.8, b = 0; a = 0.8 },
SpellID = 26297,
Name = "Berserking",
};
It seems the old spell was removed at some point. I think the new number should be the current spell for the Troll racial.
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If you still have trouble, simply uninstall RPB and reinstall it from curse.com, then apply the above fix. I believe I am still getting some errors from RPB which is what Buduga was posting. that's a debug listing from his error catcher. I use Swatter to silence errors after the first time they appear. handy addon if you have older outdated addons that still work but throw errors. I also read on another site that the author if this addon is no longer interested in updating it. so unless someone picks up this progject and continues it, this is as good as your going to get for a fix.
Cheers!