Error 1904: Installing SP27 Fails to Register craxddrt.dll

Right-clicked and elected to run CRforVS13SP27_0-10010309.EXE as an Administrator.
Made sure no other Crystal Reports process was running in the background.

Side note: Received a message about needing to close a FlexNet process but, when checked, that process was no longer running. So that process is probably transitory.
Upon clicking Retry, the installation process continued and later generated the following failure message:

A search shows only a few similar failures in the past several years, but no clear/relevant answers. For example, at some point in the past, using SP14 instead of an older SP fixed that problem.
Any known reasons/solutions for SP27?