I am sorry I can not solve this problem. No idea, anyone can help me.

Now I am developing a Java App, and the problem is sometimes the browser 
returns me a surprise: 404 file not found.

My system is as usual, (IIS, Oracle, IE, Java...). When only one client is 
there, nothing is abnormal. When several sessions are aroused, this 404 
error may jump out somewhere sometime. 

Who knows what is the possible reason?

Thanks in advance.

From Sun.
4/26 Tokyo