Apple
has posted an update to address this issue:
http://www.apple.com/finalcutexpress/download/ (for FCE)
http://www.apple.com/finalcutstudio/finalcutpro/download/ (for FCP -- requires login)
I did not know that since I do not use FCE that much, especially not on any newer machine that may have PCI-Express architecture.
At the time that Final Cut Pro and Final Cut Express were written, PCI-Express wasn't anywhere to be found -- the only way for Apple to have programmed FCE and FCP for this was for them to see into the future... not very likely, considering I stole Jobs' crystal ball last time I had dinner with him.
PCI-Express is an extension of the PCI bus architecture, and therefore is seen by the computer as a regular PCI slot. Final Cut Pro and Final Cut Express require AGP graphics cards to run, and in newer Macintoshes that use PCI-E architecture, no AGP bus is present -- so the software complains. Apple released updaters for the programs soon after, so that all legitimate copies of Final Cut Express/Pro could be compatible with Macintosh computers that use PCI-E.
Still, the updaters only update the newest versions of FCE and FCP (v.3 and v.5, respectively). If you're still using Final Cut Express 4.5, then you'll have to resort to the (rather simple) hack:
1. Control-Click on the Final Cut Pro application and select "Show Package Contents."
2. Open the "Contents" folder
3. Open "info.plist" with your favorite
plain-text editor. Maybe make a backup copy first in case you accidentally save in RTF or some other format.
4. Change "AGP" to "PCI" under a string named "<RequiredIODevice>" or something similar to that.
5. Save and close "info.plist."
Optionally, you can also simply delete the line "<RequiredIODevice>" and the following line containing "AGP."
You can also use this hack in a similar fashion to run Final Cut Pro 4 / 4.5 on a G3-based machine... once you open the info.plist file you'll see how.