webservice time out

Question

i have a very weird case of web service time out.Below is what i set to prevent time out.

<system.web>
<compilation debug="false" tempDirectory="C:\.....temp\" />
<httpRuntime executionTimeout="3600"  />
</system.web>

there is one case where my web service needs to run for some 10 minutes. I need to delete the files in tempDirectory in order to make it run successfull. For example, after a successful run, i keep the service idle. after some time, IIS retrieves the resources and kills the service process. then I run it again, only this time the service will fail with a "request time out" error. But after deleting the files in tempDirectory, it runs normally again. it seems after IIS restarts the service, the configuration does not work anymore, need to trigger a recompilation of the service to make it work.

my IIS version is 6.