Losing sound with transitions

I'm using a sony TRV-33 miniDV connected with a Firewire
card to my computer. No problems with capturing my video (
in DV-AVI) but when I put my movie together I get either a
popping sound with some transitions or the music is
temporarily lost during the start of a transition. What do
you think is causing this and what can I do about it.

I have a Dell P4 (2.2) with 1 gig of RAM.