Yep, getting the same error here too.
The difference here is that I get it EVERY time I try to add an extra animation to the panel.
The computer has been on all day without a restart, with 3D Max, Photoshop CS3, Visual Studio, and a few others running, so maybe restart may be in order (I'll post again if it makes a difference).
Also, once it has given the error, the app crashes completely within a few seconds.
Sponge.