DrugPak Classic operation relates to a file found at C:\Windows\ADS.ini as well as other .ini files that are stored in the C:\Windows folder. That folder is only fully accessible by an administrator.
Windows has a potential to create an alias of these files (and anything from the C:\Windows folder). Where DrugPak operates successfully when logged in as an administrator but not through other users, this indicates that an alias has been created and that it differs from the original file in some way. The solution to this condition is to delete the alias file.
On a Windows 10, 8 and 7 workstation the file(s) to delete is found in C:\Users\%username%\AppData\Local\VirtualStore\Windows In Windows2008 Server this file is found at either %HomeDrive%\Windows or %UserProfile%\Windows Open that folder and delete any of the following files that may exist; ads.ini, dp32.ini, drugs.ini, dpi32.ini, dpmro32.ini. (The references %username%, %HomeDrive% and %UserProfile% will only go to the proper location when logged into Windows as the user who is experiencing the problem.) These alias Windows folders are NOT reflected in searches of the hard drive, and so if you were to search for ADS.ini, it may exist in one of these folders but would not be indicated in the search (and the search will only find the instance that is in C:\Windows and opening that file will illustrate the contents of that C:\Windows instance).
If Windows chooses to re-establish the alias copy of the file, it would do so based on the current C:\Windows instance of that file, and that is fine.