I’m having exactly the same issue. Running Final Cut Express on Lion, have been doing voiceovers for years with no issues whatsoever. With Lion though, simply clicking the voice over option causes FCE to lock up. No option but to force quit.
The most annoying thing is that I’m running an early 08′ MacBook which doesn’t support FCP or the new FCX. If no fix or update is available I’ve got no option it seems but to cash out and upgrade my computer.