Don't you have an error handler which tells you exactly which line gives the error?

>I can show the main.prg through which is set as main: ( I think it is due to this )
>
>

>On Shutdown do cleanup()
>
>*-------------------------------------------
>*--
>*-- Runtime Mode Application Startup Program
>*--
>*-- Entry point for front-end application
>*--
>*-------------------------------------------
>
>*-- Include
>#INCLUDE foxpro.h	&& !!!@@@
>
>
>*-- Clear all at first
>CLEAR
>CLEAR DLLS
>RELEASE ALL EXTENDED
>CLEAR ALL
>
>PUBLIC DEBUGMODE  && TRUE when running within VFP, FALSE for standalone program
>PUBLIC gcHomePath && Working directory
>*Public True 
>Public want_to_exit
>
>*-- DECLARE DLL statements for the temporary directory
>DECLARE INTEGER GetTempPath IN Win32API ;
>  INTEGER nBufSize, STRING @lpszTemPath
>PUBLIC gcTemPath  && Temporary directory
>
>*-- DECLARE DLL statements for the copying an existing file to a new file
>DECLARE INTEGER CopyFile IN Win32API ;
>  STRING @lpExistingFileName, ;
>  STRING @lpNewFileName, INTEGER bFailIfExists          
>
>*-- DECLARE DLL statement for beeping
>DECLARE INTEGER MessageBeep IN Win32API AS MsgBeep Integer sound
>
>*-- Set up the path so we can instantiate the application object
>IF SetPath()
>  *-- Init startup and message loop
>  *DO FORM MAIN
>
>  *Do Form Golform
>  Do Form loginform
>  *READ EVENTS
>  Release All 
>  Clear All 
>  Close All
>ENDIF
>
>*-- If inside VFP run Project Manager again
>*!*	IF DEBUGMODE
>*!*	  ACTIVATE WINDOW "Project Manager"
>*!*	ENDIF
>
>*-- Clear all at exit
>CLEAR DLLS
>RELEASE ALL EXTENDED
>CLEAR ALL
>
>*-- End of program
>*--------------------------------------------
>
>*--------------------------------------------
>*-- Set path to application working directory
>*--------------------------------------------
>FUNCTION SetPath()
>*-----------------
>
>  LOCAL lcPath, lcBuffer
>  LOCAL lnStart
>
>  lcPath = SYS(16)                              && Where we were executed...
>  lnStart = AT("\\", lcPath)
>
>  IF lnStart = 0
>    lnStart = AT(":", lcPath) - 1
>  ENDIF
>
>  IF lnStart > 0
>    lcPath = SUBSTR(lcPath, lnStart)            && Derive program name
>  ENDIF
>
>  gcHomePath = LEFT(lcPath, RAT("\", lcPath))   && ... and path to it
>  *gcHomePath = "d:\coolpos"
>
>  *-- Change current directory to working...
>  CD (gcHomePath)
>
>  *-- If we are running MAIN.PRG directly, then
>  *-- CD up to the parent directory
>  IF RIGHT(lcPath, 3) = "FXP"
>    *-- One level up
>    CD ..
>
>    *-- Assume we were run from VFP
>    DEBUGMODE  = .T. &&TRUE
>
>    *-- Make out path to INI file
>    gcHomePath = LEFT(gcHomePath, RAT("\", gcHomePath, 2))
>
>    *-- Ensure the project manager is closed
>    DEACTIVATE WINDOW "Project Manager"
>  ENDIF
>
>  *-- Set all pathes
>  SET DEFAULT TO (gcHomePath)
>     SET PATH TO Classes, ;
>	            Forms, ;
>	            Includes, ;
>	            Menus, ;
>	            Pictures, ;
>	            Graphics,;
>	            Graphics\Bitmaps,;
>	            Graphics\Pictures,;
>	            Graphics\Pictures\Logo,;
>	            Graphics\Pictures\Icons,;
>	            Graphics\Pictures\World\Flags,;
>	            Graphics\Pictures\World\Maps,;
>	            Graphics\FormImage\formbase,;
>	            Graphics\FormImage\formbutton\black,;
>	            Graphics\FormImage\formbutton\blue,;
>	            Graphics\FormImage\formbutton\Green,;
>	            Graphics\FormImage\formbutton\General,;
>	            Graphics\FormImage\formbutton\Red,;
>	            Graphics\FormImage\formbutton\Yellow,;
>	            Graphics\FormImage\formhead,;
>	            Graphics\FormImage\formtheme,;
>	            Progs, ;
>	            Procs, ;
>	            Data, ;
>	            Scripts
>  SET PROCEDURE TO Measure
>  SET CLASSLIB  TO && !!!@@@
>
>  *-- Temporary path
>  lcBuffer = REPL(' ', 511) + CHR(0)
>  lnStart  = GetTempPath(512, @lcBuffer)
>
>  If lnStart > 0
>    gcTemPath = LEFT(lcBuffer, lnStart)
>  Else
>    gcTemPath = gcHomePath
>  Endif
>
>  IF RIGHT(gcTemPath, 1) <> '\'
>    gcTemPath = gcTemPath + '\'
>  Endif
>
>  Return .T. &&TRUE
>
>Endfunc
>
>Function cleanup
>   *If want_to_exit
>      Clear Events 
>      Clear All 
>      Release All 
>      On Error 
>      On Shutdown 
>      If _vfp.StartMode = 0
>         Return To Master 
>      Else 
>         Quit
>      Endif 
>   *Endif
>