Capturing 8mm Videotape

I use Premiere CS3 to capture video.  Capturing video from VHS or Mini DV tape, I almost never have dropped frames.  I captured about 25 minutes of 8 mm videotape.  There were 500 dropped frames.  The problem was not with the tape, because it played fine on my television. 

My computer is a Pentium D with (2) 3.00GHz processors.  I have 2.48 gigabytes of RAM.  The hard drive is an ATA/ATAPI.  The computer is five years old.