Dropout after capture DV or HDV

Strange dropouts after I capture DV or HDV. Like small colored squares over the video image and sometimes with audio breaks on the same place. These are not on the tape, when I preview it on a TV connected directly to the deck or camera its fine. This problem appears when I capture from FCPro with AppleProRes HQ, HDV and DV Pal codecs over FW. I use external hard drive G-RAID2 as a capture scratch disc, connected with FW800 cable.

I tried to capture these on my internal system HD, then I copied it to the external G-RAID2 and the material was fine. The only problem is when I playback it from FCPro timeline sometimes there is synch problems. The video is delaying or audio is running with very frequent breaks. When I stop it and start playing back again, its OK, but later comes again.

My computer configuration is: 4 x 2.5 GHz PPC G5 Quad, 4.5 GB RAM, Mac OS 10.4.11, FCS 6 with latest update, AJA Kona LH and Alesis FireWire Audio Mixer for audio monitoring.

I still haven't tried to capture with AJA, because I don't have desk with RGB or SDI output at that moment. This configuration was working fine over the last year. The problem appeared last week. I didn't change anything, it just appeared.

Does anybody have an idea about it?

Thanks in advance!

Yes, although the audio mixer is connected to FW400 port. I disconnected the mixer and seems the synch is better. I will test the capture as well. Do you think if I add additional FW card and connect the mixer there it will be separate buss?

Kalin