If you use UnvDoc for BO 4.1 SP12, 4.2 SP6, you may encounter the following errors.
“Unable to cast COM object of type ‘Designer.ApplicationClass’ to interface type ‘Designer.IApplication’.”
“The RPC server is unavailable”

“QI for IEnumVARIANT failed on the unmanaged server”

The issue is caused by an error in Universe Designer Tool API introduced in some of Service Packs
of SAP Business Objects. We are not able to fix it on our side. Hopefully it will be resolved in future Service Pack or Patch.
We do not know yet the exact Service Pack when the issue was introduced. UnvDoc should fully work for BO 4.1 SP7, 4.2 SP3.
Workaround
As workaround, you should avoid importing universes using UnvDoc tool. Instead follow the following steps:
- Login to Universe Design Tool and import universes that you want to export to Excel. Close UDT.
- Open UnvDoc and login. Open the universes using the button “Open…”
- Export metadata to excel using “Quick View” or “Save to Excel”