Sorry I can't send all code here. it's a little big.
When i use php4. I build a big class(with a long string)
I build a "inc" file for it. then include it in another 
file.
IIS: 
At first it looks fine. But when i add more 
functions and members into it. first time is good. when I reloaded it or opened it in another browser. php told me redefine class.but i only include it for one time. But when I waited for a while. It worked again. 
Apache:
So I run it in apache (when the class is small it's also fine). php crashed(exception error). I had try it in win98+apache 1.3.12. the result is same.

I can't run php4 in win98+pws. 

It looks like php use memory in wrong place. and don't clear it in time.