allegro dbdoctor
Regarding confusion,
It is created by people loosely referring to Capture and CIS as "Allegro Schematic".
Cadence bought OrCAD (both Capture and Layout tool) some years ago
Capture is used and some how integrated as front end tool for creating netlist to ALlegro.
Recently Cadence dropped further development for Orcad Layout.
In addition native schematic tool for Cadence is Concept.
Now regarding error you are receiving, as you have not mentioned which version of Allegro you are using, judging by your post looks like is 15.XX or above if your layout house uses version 14.XX or lower then you have to run DB Dr. to upgrade to higher version.
I have never encounter any issue running DB Dr. Always worked fine.
HTH,
M