Is the AG-DVC30 in "Play" mode?

Which Mac?
Version OSX?
Version FCE?
Has this worked before with this specific camcorder and computer? How about any other miniDV tape camcorders and this computer?
Have you tried importing with iMovie?

On the Mac - is the firewire port active? How do you know? (System Prefs: Network... Under the Apple; About this Mac)

On the Panny, is the DV port working? Has the firewire cable ever been inserted or removed when the camcorder was ON?

Do you have access to another computer to check?

You are not alone
http://discussions.apple.com/search.jspa?q=ag-dvc30&dateRange=all&rankBy=10001&start=15

I've read through a few without a solution for you, yet...