aqEnvironment.GetEnvironmentVariable fail

I have a script which uses the following line

  HOMEPATH = aqEnvironment.GetEnvironmentVariable("HOMEPATH")

This fails the script (i.e. the files do not get deleted as they should per the script).

I will add that this works fine in Testcomplete12 on my desktop - but on the server running TestExecute12 it fails and it outputs the Log.Error message

If I replace it with the hardcoded path, it works

  HOMEPATH = "C:\users\builduser\"

Full script is below - any suggestions why this occurs?

Sub DeletePDFFiles
  ms = 5000
  HelpStr = "Delaying script for " & ms & "milliseconds."
  aqUtils.Delay ms, HelpStr
  
  Dim spath, spath2, HOMEPATH
  HOMEPATH = aqEnvironment.GetEnvironmentVariable("HOMEPATH")
  sPath1 = HOMEPATH & "\Downloads\ClaimForm*"
  sPath2 = HOMEPATH & "\Downloads\xxx_UK_xx_xx_xx_T_And_C_2016*"
  cPath1 = HOMEPATH & "\Downloads\ClaimForm.pdf"
  cPath2 = HOMEPATH & "\Downloads\xxx_UK_xx_xx_xx_T_And_C_2016.pdf"
  If aqFileSystem.Exists(cPath1) Then
    Log.Message "Claim Form Doc Found!"
    aqFileSystem.DeleteFile(sPath1)

    If Not aqFileSystem.Exists(cPath1) Then 
      Log.Message "ClaimForm Doc Deleted"
    Else
     Log.Error "ClaimForm NOT Deleted"
    End if

  Else
    Log.Error "Claim Form Doc NOT Found!"
  End if

  If aqFileSystem.Exists(cPath2) Then
    Log.Message "T&C Doc Found!"
    aqFileSystem.DeleteFile(sPath2)

    If Not aqFileSystem.Exists(sPath2) Then 
      Log.Message "T&C Doc Deleted"
    Else
     Log.Error "T&C Doc NOT Deleted"
    End if

  Else
    Log.Error "T&C Doc NOT Found!"
  End if

End Sub