tomcat suddenly stops

[Sanjay Kashyap]

Environment  is following

Server:NT4 sp6
jdk1.3.1
tomcat3.2.3

My system has been using Oracle8.1.7 IIS4.0 and  Javamail1.2,
but tomcat suddenly stops one time a day these days.
When it's stopped, if try to connect to URL, it says "Page is not found".
Without rebooting the tomcat, it will be connected URL correctly after few
minute later.
If you have any idea about problem, like setting of TOMCAT,
could you tell me the solution ?

Thanks