I've been working on my customer's new server, attempting to move my 18.0 application, including webapp, over to it. So far so good, Server 2012/R2 and SQL Server 2014 Express. The one thing that I haven't been able to get to run is the 18.0 Webapp. It tries to run but then I get an error 500 on the browser and the following error in the Windows Event Viewer.

Invalid web application %1. Please verify that the spelling is correct and that the specific web application has been correctly configured.
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I've uninstalled the webapp, deleted it in iNetMgr, recreated it and no joy. Verified global.asa is correct as is webservice.wso.

The Web order example works fine on this server.

Any clues as to what this error might mean?