Visor drop-down terminal gives error on launch

I've used various Linux OSes for a long time but I'm still a Mac newbie.
One app I really like in Linux is the drop-down terminal Yakuake and I was glad to discover that Visor does basically the same thing in OS X.
So, I installed Visor and included terminal.app in my login items as instructed.
However, on booting to Leopard, the first indication of the presence of Visor is this error message:

SIMBL Error
Failed to load the Visor plugin.
-[QCComposition _initWithBacking:]: Inconsistent state

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But, after I OK this error, Visor becomes totally available via the hotkey without any problems.
Does anybody know the significance, if any, of the error message?

tuffluffjimmy said:

How did you install it? do you have any other SIMBL extensions running? Are you actually experiencing an error or did you just read that error in the console?

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Hi, thanks for the reply.
Answers to yr questions:

1. Installed as in the link I gave
2. No
3. The error pops up on the desktop just after boot (terminal.app autostarts) -- not in the terminal

I resolved this by unchecking the Use Quartz Animation box in Visor preferences. Learnt about this here.