I can't modify anything of the ACL of the ipmgui.exe file (or any file of Avira in the same directory).
It's not working at all with any cacls line tried, even under a system prompt! I'm not sure at all it's related to ACL, as they are looking simple. Maybe a protection from Avira?
Here are the cacls dumps.
cacls "C:\Program Files (x86)\Avira\AntiVir Desktop\ipmgui.exe"
C:\Program Files (x86)\Avira\AntiVir Desktop\ipmgui.exe AUTORITE NT\System:(ID)F
BUILTIN\Administrators:(ID)F
BUILTIN\Users:(ID)R
APPLICATION PACKAGE AUTORITY\ALL APPLICATION PACKAGE:(ID)R
C:\Program Files (x86)\Avira
BUILTIN\Administrators:(OI)(CI)R
BUILTIN\Administrators:(ID)F
CREATOR OWNER:(OI)(CI)(IO)(ID)F
AUTORITE NT\System:(OI)(CI)(ID)F
BUILTIN\Administrators:(OI)(CI)(IO)(ID)(Special access:)
READ_CONTROL
SYNCHRONIZE
FILE_GENERIC_READ
FILE_GENERIC_WRITE
FILE_READ_DATA
FILE_WRITE_DATA
FILE_APPEND_DATA
FILE_READ_EA
FILE_WRITE_EA
FILE_READ_ATTRIBUTES
FILE_WRITE_ATTRIBUTES
BUILTIN\Users:(OI)(CI)(ID)R
NT SERVICE\TrustedInstaller:(CI)(ID)F
I'm using Windows 8.1 up to date.