Strange Problem w/ DimPro v1.5 Microhost -- Error Loading Exp Pack Programs

I found a solution to the problem and thought others might have the same problem.
 
Background:
-- Fresh Install of Sonar 8.5 Producer
-- including install of Dim Pro 1.2 from Sonar 8.5 DVD 3 (DVD drive is Drive E)
-- including install of Expansion Packs 1&2 from Sonar 8.5 DVD 4 (DVD drive is Drive E)
-- including install of v1.5 Update (including Microhost) from C: drive (downloaded)
 
Problem:
When loading ANY of the Expansion Pack 1&2 Programs I receive a "Dimension Pro.exe -- No disk" error (see attached image)
 
The error only occurs if ALL of the following conditions are met:
    -- loading programs via the Dimension Pro Microhost (no error with VST version through Sonar 8.5)
    -- Expansion Pack 1 and 2  (all programs) [all other Dimension programs load w/o any error]
 
Solution:
Where error message is received:
 -- click "Continue"  (samples load)
 -- click the "Program Handling button and select "Save Program"
 -- The problem is fixed for that single program
 
QUESTION:  Can anyone explain why I am getting this error and why re-saving the program fixes the problem?