Anyone else having this problem: installing the M100 codecs on my dual 1Ghz G-4 (OSX4.2, QT 7.01) won't allow FCP to open (crashes instantly during opening). Uninstalling is currently the only found solution. M100 8.2.2 and a Vincent 601 card installed on this system.
Have you uninstalled the hardware codec (the Media 100 codec.component)? It cannot be the software codec alone, since these run fine with FCP. Or maybe your codec file got corrupted; try to download the sw codec again and see if that changes anything.