Portal Application times out.

I have developed a portal application on EP6 SP2 on windows.

Everything works fine, except we are getting intermittent

runtime errors. It appears as if the component has been

removed from memory. This happens after a variable amount

of time. It appears to happen more frequently

when there are more users testing the application simultaneously.

There are RFC calls to te R3 back end, but it is not only these

that fail.

Any suggestions?