Check that the Mac is in 32 bit mode:

By default all new 5,1 2010/2011 MacPros boot in to 64bit mode.
However, Quicktime does not support 64bit mode and many 3rd party drivers used with catalyst are not compatible with 64bit mode. (including Active Silicon)
SOLUTION:
Force the Mac to boot in 32bit mode.
To select the 32-bit kernel for the current startup disk, use the following command in Terminal:

sudo systemsetup -setkernelbootarchitecture i386

This will allow the Mac to boot in to 32bit mode permanently
(an alternative command is available to boot in to 64bit mode)


If this doesnt work:
remove the cards
start with a blank catalyst show with no settings
check it runs correctly

re-install one card - and check again
then
re-install next card - and check again

Dont use old show files when changing versions or OS - always start from a blank catalyst show (ie no settings)

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