I get these errors when trying to Export an XRay report from a geodatabase in ArcCatalog for a particular database. I have created a report on this database before, and can still create one for other databases - why it doesn't like this database right now is beyond me..
Problem During Load
Problems came up in the following areas during load:
This file cannot be opened because of errors. Errors are listed in: ....c:\users\login\appdata\local\microsift\windows\inetcache\content.mso\bb634191.log
(and then this one comes up)
Exception from HRESULT: 0x800A03EC
Please ensure you have Microsoft Excel installed.
Also there may have been an Excel problem that you could see in the Windows Task Manager: do you have duplicate dataset names in the Geodatabase across multiple schemas?
Then I hit OK and get a Failed to Export geodatabasename error.
I last ran XRay in May successfully on this database in April. I am not sure what has changed... maybe some Windows/Microsoft patches in the background?? Maybe a new feature class or domain?! No new ArcGIS (running 10.5.1), XRay, or Excel (2013) installation.
I found a related thread - Error: Exception from HRESULT: 0x800A03EC when loading an XML using X-Ray for ArcCatalog - that might explain why you're seeing this error. Does this apply to your configuration?