Why our Dominino R5 server is not working on Win2K?

[echain]

We install the internal Domino server R5 in our company for some testing. The Operating system is Win2K. We can not turn on the R5 server.
The error message: Unable to create Server task: Cannot create thread
Thread=[0890:0004-0754]
PANIC:LookupHandle:null handle

nserver.exe Application Error
The exception Breakpoint A break point has been reached (0x80000003) Occurred in the application at location 0x77f9eea9
It happened the second time, When I reinstalled the R5 last time, it was working for a month, but the problem came back again
Anyone can explain to me what is going on this server?
Thanks!!!!!

 

[Llap]

Try W2K SP1 (do not install or deinstall IIS, if you don't use it) with at least R5.05 Domino
Installed about 50 servers, never had a problem