Craig,
The default installation for COM servers in IIS 5 is Protected(Medium pooled) even without full MTS meaning errors in the COM app will not take down the web server.
ComReturnError catches those errors within the app that will cause crashes so that the application will fail gracefully and recover with the next hit.
Full MTS is an option - I don't think I said anything bad about MTS..
>>Thanks for sharing all of this info. Our setup is different since we aren't using MTS and COM+ and we are just using dbfs - so it's probably better suited to ComReturnError.
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>I think you have some misinformation. There are valid reasons to use MTS/COM+ in your situation. The component will run in MTS/COM+ memory, not IIS. This means you don't have to down the web server to update components. You also won't crash the web server is the component crashes.