Logic Pro 9 hangs when scanning Audio Units

Hi everyone,

I'm having some issues with Logic Pro, it's being run for the first time after a rebuild but it seems to just hang when trying to scan for audio units. I get this message:

+"Logic Pro will now test 40 installed Audio Unit plug-ins to maximize system stability. This AU validation can take some time. Subsequent launches of Logic Pro do not require this test and will be much faster."+

I then get a progress bar and a "Scanning Audio Units (finalized 0 of 40)" box with an abort option. The abort option doesn't do anything but I can still quit Logic using the cmd+Q shortcut.

So far I've tried -

1.) Booting into Logic without Core Audio and opening AU manager. It starts up but for some reason the manager simply refuses to open. I click on it and nothing happens.
2.) Deleted the com.apple.audiounits.cache in my ~/Library/Caches/ folder.
3.) Updated Logic to the latest version (9.1.3, was on 9.0.0)
4.) Removed all my NI Komplete 7 components from the /Library/Audio/Plug-ins/Components folder. This simply made Logic think there were only 22 AUs to scan instead of 40, but it still wouldn't do anything.

Oh and if it makes any difference I'm running a Mac Pro (2 x 2.8 Quad Xeons, 4GB RAM, OS 10.5.8)

Any ideas as to why Logic is hanging like this?

Cheers, Dan