You could capture to the local drive, then move the media with the media manager (use copy then reconnect before you trash the originals) but that’s a pain…
I’ve got a suspicion that it’s the FW setup you have going on there… might try adding a firewire hub, but that also might cause some problems.. I’ve heard of problems and also heard it works OK..
Only other thing to try that I can think of is to trash your preference files. and give it another go… which deck are you using?
Jerry