WBRM Install fails on Win 2016 Server

[k2dnn]

Please note that the current install was on win 2012 and the migration target is win 2016 (I didn't try to install there, yet).

As in subject, both passwords (SA and serveradmin) checked and not containing any of the forbidden characters.

Windows Installer installed the product. Product Name: WBRM - A Backup, Restore and Migrate Utility for use with MSPControl, WebsitePanel and SolidCP WBRM - version 7.4.66. Product Version: 7.4.66. Product Language: 1033. Manufacturer: WBRM, LLC. Installation success or error status: 1603.

Product: WBRM - A Backup, Restore and Migrate Utility for use with MSPControl, WebsitePanel and SolidCP WBRM - version 7.4.66 -- Installation failed.

[k2dnn]

The installation was successful when run as administrator which is weird and shouldn't happen as SQL access is based on SA credentials.
At least it should be posted in FAQ or something.
I'm not happy....