Get last InstallDir - problem

[Smurge]

Hello

NSIS have a very good documentation, in fact the best i have ever seen in a freeware tool.
I made an installer script and it worked so far, but i tried to insert an exist check of previously installed versions of my program.
I want to determine where it was installed and use that directory as the default output directory at the Install Page.

So i let the installer write the used InstallDir into the registry (no problem there). The installer should look at the start, for the regkey that is written by previously installations.
btw. I realised that the "Goto" thingie does not realy work like the Windows Batch "Goto". When ther there are 2 identical variables to define, the compiler exits with an error, even if is jumped with a "GOTO"! ... but this is another story.

Here is the part of the script that does not work: (everything above the CALL is OK!)

PHP Code:

;------------------------
Function .onInit
            ; # GET FILE VERSION FROM MyPROGRAM.EXE
            ; http://nsis.sourceforge.net/Invoking_NSIS_run-time_commands_on_compile-time
                    !system "..\plugins\GetVersion-from-MyPROGRAM32\GetVersion-from-MyPROGRAM32.exe"
                    !include "..\plugins\GetVersion-from-MyPROGRAM32\Version.txt"
;            ; # cut from the 2. right position for the title name -> Caption "MyPROGRAM - ${VERSION2}"
                    StrCpy  $1 "${VERSION}" -2
                    !define VERSION2 "$1"

CALL alreadyexistcheckfunktion

FunctionEnd


;-----
; - ALREADY EXIST INSTALLATION? - if yes, then get the install directory into -> InstallDir "$(TARGETDIR)", otherwise set default instal dir

Function alreadyexistcheckfunktion
    ; # check key existence
ReadRegStr $0 HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\MyPROGRAM"  "InstallPath"
    IfErrors jumpout ""
     MessageBox MB_ICONQUESTION|MB_YESNO "Looks like MyPROGRAM is already installed$\r$\n$\r$\nDo you want to continue the installation anyway$\r$\nand update MyPROGRAM?" IDYES alreadyexistcheckout
    ; # aborting end EXIT
    MessageBox MB_ICONINFORMATION|MB_OK "Stopping installation process"
    Abort
;---------EOS
alreadyexistcheckout:
        ReadRegStr $1 HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\MyPROGRAM"  "InstallPath"
        !define targetdir $1
        Goto jumpoutout
jumpout:
    !ifndef targetdir
        !define targetdir "$PROGRAMFILES64\MyPROGRAM"
    !endif
jumpoutout:
FunctionEnd

.
.
.

InstallDir "$(TARGETDIR)"
Caption "MyPROGRAM - ${VERSION2}"

;------------------------ 


The setup is OK but the compiler finish with a warning:
1 warning:
LangString "TARGETDIR" is not set in language table of language English

1. Question: what is the connection of this Function and the "language table of language English" ?

The Setup starts correctly.
-at the first time the InstallDir is empty.
-the second time, the Windows Title (caption) got the the $(targetdir) of the previous installation (=>MyPROGRAM - "C:\Program Files\xyz"), and the "InstallDir" @ the InstallPage is empty, too!
What went wrong?


I tried another way:
When i change "Function alreadyexistcheckfunktion" to "Function .onGUIInit" the compiler exits with:

PHP Code:

Error: Function named ".onGUIInit" already exists.
Error in macro MUI_FUNCTION_GUIINIT on macroline 2
Error in macro MUI_INSERT on macroline 11
Error in macro MUI_LANGUAGE on macroline 7
Error in script "stdin" on line 208 -- aborting creation process 


linie 208 is-> "!insertmacro MUI_LANGUAGE "English""

2. Question: What does this function have to do with the macro at all?
Isnt it alowed to use the ".onGUIInit" in the main .nsi file??


3. Question: Why does the window title change into the InstallDir and the default install page is empty?

I would be very thankful for any help!

bye