If you go into IIS for our site and go into the Home Directory area, click on the Configuration button. You will see a "Cache ISAPI Applications" option. You should ONLY turn this off for testing purposes. When you turn it off, if two people try to hit the same page at the same time they will get:
The requested resource is in use
When this is off, you will also see an event log entry for EVERY time an ISAPI is loaded and unloaded from memory - i.e. constantly.
Check this box in order to cause the items to cache in memory - therefore always being available.
Also:
We ran into this problem and it was due to a corruption of the vbscript.dll as we noticed it was not running.
