The April 15th Info Alley (and TIL file 0021164) reports:
Q. When Avid Cinema is launched, all menus except the File menu are dimmed and the only menu item available is Quit. What's happening?
A. This may happen after installing America Online (AOL) 3.0. Some versions of AOL 3.0 install ObjectSupportLib 1.1.4. ObjectSupportLib 1.1.4 is incompatible with Avid Cinema and will cause the behavior you described. The solution is to drag the ObjectSupportLib file from your Performa CD into your Extensions folder, replacing the incompatible version, and then restart.