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I've had several similar reports in the past. You can search your registry for references to this file.
Start searching HKLM\System for any occurances of 'ias\ias.xml' and you'll probably have one or more references.
Depending on the exact registry path where the reference is found, I would try to delete (backup first!) the registry value or the complete key (eg: if it is a service, which is no longer available).
You also might need to reboot the server afterwards, before the error will go away.
If you cannot find it under HKLM\System, you can try a search starting at the HKLM toplevel.