Here, try running this script. It will output a bunch of information which can help
you to track down what might be causing the issue.

Break On
Dim $SO
$SO=SetOption('Explicit','On')
$SO=SetOption('NoVarsInStrings','On')
$SO=SetOption('NoMacrosInStrings','On')
 
color g+/n
'Verifying Call Tracking Software is installed.' ?
'Returning information to debug the script.' ??
'Current User: ' + @UserID ?
'KiX Ver: ' + @KiX ?
'KiX Type: ' + @ScriptExe ?
'KiX Starting Dir: ' + @StartDir ?
'Script name: ' + @ScriptName ?
'DOS Ver: ' + @DOS ?
'Domain Membership: ' + @Domain ?
'Logon Domain: ' + @LDomain ?
'Logon Server: ' + @LServer ?
'Logon Drive: ' + @LDrive ?
'Logon Mode: ' + @LogonMode ?
'Site: ' + @Site ?
'Script Dir: ' + @ScriptDir ?
'System Folder: ' + @LanRoot ?
'System Date: ' + @Date ?
'System Time: ' + @Time ?
'Product Type: ' + @ProductType ??
If InGroup('KIXInstallCT')
  Dim $W
  'User found in group KIXInstallCT' ?
  Sleep 5
  If Not ReadValue('HKCU\SOFTWARE\RunOnce','cal2')
    'Reg read returned: ' + @ERROR + ' - ' + @SERROR ?
    SHELL '%windir%\system32\msiexec.exe /i \\Fldavrep01\calltracking\PSCallRecordingSetup\PSCallTracking_Setup.msi /qb-'
    'Install returned: '  + @ERROR + ' - ' + @SERROR ?
    $W=WriteValue('HKCU\SOFTWARE\RunOnce','cal2',1,REG_SZ)
    'Write to Reg returned: '  + @ERROR + ' - ' + @SERROR ?
  EndIf
Else
  color r+/w+
  ? 'WARNING!' ?
  'User not found in KIXInstallCT group' ??
EndIf
 
Dim $Pause
color g+/n
'Script is completed, press any key to continue.' ?
Get $Pause