Just to clarify, I’m using Vegas Movie Studio Platinum. I captured clips with Vegas. The frame grabs were done using Nero Media player but the problems are there no mater which software you use to watch the clips.
Since my last post I tried to capture video using CapDVHS (free program) and in 5min clip I couldn’t find any problems while in Vegas clips I had glitches approximately every 20-30 sec but not in regular intervals.
I live in Australia and my Sony HC1 is PAL version.

You already have the answer: ALWAYS capture with the free CAPDVHS utility. It is BY FAR the most reliable capture program.
I've had your problems very often when using Cineform's capture tool. Also the internal Vegas capture software is not completely stable on my machine.
Use cineform (or Vegas) later to convert the m2ts to intermediate format, if you wish.
Martin

Cineform Connect HD is absolutely reliable, in my experience of v1.5 to current, in capture of m2t and generation of intermediate avi files, although there was a problem with v1.8 with Athlon processors. If you find otherwise then you should check whether you have a problem of procedure. However Connect HD isn't free.

1. I've yet to have a problem with Vegas cap for HDV.
2. I've yet to have a problem with CineForm since version 1.2
3. No problems with CapDVHS, either.

Your errors look like what I'd expect to see with CF24, and/or also using lower field first.
More info about your project/timeline would be helpful here.

Sorry folks, but on my machine (Win XP, 3.06 GHz HT) all Cineform versions (except 2.0, which I haven't tested yet) made problems during capture. Every now and then a few frames were distorted with a couple of faulty MPEG-blocks.
I've had an intense discussion with Cineform support about this (even sent them frame grabs). They were very cooperative but in the final end they couldn't do much. The error was not 100% repeatable as on recapture the distortion would appear elsewhere (but it always happened after a while). I never ever have experienced anything like that when using Capdvhs - that's why I'm recommending it.
Maybe my computer is too slow - I don't know. What I know for certain is that this machine is absolutely clean and no background processes are stealing resources. I'm very careful about these things...
Martin

mdopp,
I'm running a 3.06 GHz as well, and not having issues. It might be machine config, I dunno. Even on a 3.06GHz laptop, I don't have problems with CineForm's capture, although with V1.2 of their software, I had some serious blocking that crept in. One thing I have noticed from time to time with certain frames that are extremely close in chroma and have high motion is that I occasionally see some color shift on the edges of the gradient that I can't see in the m2t frames. Of course, this isn't visible in the moving picture, but it's visible on a parked frame.
have you tried using EndItAll prior to capture? That might solve your problem if you've got machine config issues.