I finally managed to solve this problem. I'd given up and was working 
around the issue, then I noticed that the components that were giving me 
the problems were registered in component services. I had added them 
whilst testing something else a little while ago. Once I had removed the 
components from component services I was able to run the program within 
visual basic with no Out of memory error. I'm not sure why this had the 
effect it did but I can now debug happily.

So there you have it.
Cheers
Ian