This has been a big firewire issue between JVC and FCP. Apparently other editing systems don’t seem to have issues with TC breaks with JVC, just FCP. I use both JVC and FCP and love both of them! The solution I found was to capture the footage using DVHSCap (google it). It captures via firewire and I have never had a break in the footage. I also have a Blackmagic Intensity Pro card and capture footage with my JVC BR-50 deck using HDMI. Hope this helps. 🙂
Peter Brewer
http://www.indimax.com.au