Unable to export PST from eDiscovery

Hi

I'm trying to export a PST from an eDiscovery result in Exchange 2013.

When using the eDiscovery PST Export Tool I receive the following error:

"Export failed with error type: "FailedToRetrieveSearchConfiguration".
Details: The request failed with HTTP status 404: Not Found."

We have admin functionality disabled on our main url and use a second virtual folder/address for administration, so I wonder if this may be impacting on it.

Has anyone got any suggestions on how to diagnose and resolve the issue?

Thanks

Andy