It's a while since I was working on that project. I think maybe, but I'm not sure, it was running on a *nix server for a while, but I haven't the code available here.

However a little Super Searching brings up a few hits that may help: cgi,wait for long running external prog, forking in a cgi script and Handling long running operations started by CGI requests. Playing with the search parameters will bring up more hits.

If you don't have any joy in the next 8 hours reply to this reply and I'll see if I can dig up the old code I had for solving this problem.