I already know that this user is getting %WINVER% == $WIN_95$, based on the error message he gets ("Windows 95 not supported") and the stage of installation that he reached.

Code:
If %WINVER% Equals "$WIN_95$" Then
  Display Message Box "#ERR_LAUNCH_CONDITION_OS#\n\nWindows 95 not suppor..." -- "Windows version error!"
  Exit Installation
End
I'm using SB5.