On Power Mac G4 computers with dual G4 microprocessors, you should have version 2.7 or later of Apple CPU Plugins installed in the Extensions:Multiprocessing folder.
Symptom
Final Cut Pro stops responding, mouse clicks have no effect, or video stops playing while audio continues and the dropped frame alert appears.
Solution
Download and install Apple CPU Plugins 2.7. The software can be downloaded from article 88054 "Apple CPU Plugin Document and Software."