iimRunner allows you to run iMacros very easily under a Windows account that is different from the one that your calling code runs. This methods offers several advantages.
This feature is especially useful when calling iMacros from services, ASP, ASP.NET, PHP, ColdFusion, etc. because these kind of programs run typically under a rather restricted user account.
When you move an application created with iimRunner to a new machine, it is important to make sure that you run iMacros at least once under its iimRunner account, just to make sure you clicked "OK" to all these popups that appear (only) the first time a web browser is started.
A typical symptom if you forget this is a -322 (timeout) or -110 (macro not found) error. For the most likely cause of the -110 error see http://forum.imacros.net/viewtopic.php?p=4212 (issue #4)

If using Windows 2003/2008, make sure that you add the URLs to the IE Enhanced Security configuration or remove this tool. The IE Enhanced Security configuration can be removed under Control Panel > Add/Remove Software > Windows Components