I have upgraded to 2.0.4 and there is no change in how often the problem occurs.
There should not be anything wrong with my host, it works perfectly for anything else. When the error occurs on my site it only happens for the part I include using the php function include(). The rest loads fine.
So if anyone knows any problem with wordpress content included on a site through an include() function, then I would like to hear it.
The problem is quite annoying, could someone please help?
My current clue is that it somehow might relate to cookies in some way as it seem to happen at these times:
a) First time you visit the site
b) If you visit the time again after some time
Not totally sure yet though.
That looks like what I was looking for, thanks!
Edit:
It worked yay, thanks a lot:)