Thanks everyone for replies and pm's.
My problem now is that I also lost my favourite qbsp, vis and light. I can't remember the ones I used, which makes finding them even harder. The vis.exe displayed your progress, and the qbsp was able to compile large maps with large number os entities.
I've tried these:
But I get the exceeding max entities error from qbsp, though I think the vis may be the correct one.
(I'm obviously testing them with a map I've compiled successfully before)
Thanks for any more help.