>A thing a noticed on my computer and may or may not be related to my present problem is that VFP (the development environment) sometimes freeze completly for a couple of seconds (Do not respond will sometimes appears in the title bar). This will often occurs when I save a method, when I type "m." (freeze on the dot) or an open parenthesis. I have this problem for about 2 years but didn't find any solution for it.

Sounds like the intelligense with Thor.
If you have installed Thor, disable the intellisense.
Koen