StrCmp and invalid opcode

Yet again, my broken code or something up with NSIS 2.45?

The code below works fine and no issues.

Function .onInit

 ;various other stuff



phase2:    

    ;Prevent Multiple Instances

    System::Call 'kernel32::CreateMutexA(i 0, i 0, t "myMutex123") i .r1 ?e'

    Pop $R0     

    StrCmp $R0 0 phase3

        MessageBox MB_OK|MB_ICONEXCLAMATION "The $(^Name) installer is already running." /SD IDOK

        ${WriteErrorCode} "200" "The $(^Name) installer is already running."  ; this function calls Abort      



phase3:        

     ;Check min disk space requirements

    !ifndef DEVELOPMENT

 ;more stuff

The code below does NOT work. Soon as one launches the installer, you'll get "Installer corrupted. Invalid opcode"

Function .onInit

 ;various other stuff



phase2:    

    ;Prevent Multiple Instances

    System::Call 'kernel32::CreateMutexA(i 0, i 0, t "myMutex123") i .r1 ?e'

    Pop $R0     

    StrCmp $R0 0 +4

        MessageBox MB_OK|MB_ICONEXCLAMATION "The $(^Name) installer is already running." /SD IDOK

        ${WriteErrorCode} "200" "The $(^Name) installer is already running."  ; this function calls Abort      



phase3:        

     ;Check min disk space requirements

    !ifndef DEVELOPMENT

 ;more stuff

What gives? Why do I need a tagged goto location instead of just using line numbers?

What gives? Why do I need a tagged goto location instead of just using line numbers?

Relative jumps specify the number of INSTRUCTIONS to jump, NOT the number of LINES in your script to be jumped.

This is documented in the "Relative Jumps" section in the manual: http://nsis.sourceforge.net/Docs/Chapter4.html#4.4 (Note also the part where the manual mentions using "macro insertion" and relative jumps)

Perhaps it would be best to avoid using relative jumps for now? They can make script maintenance difficult so I rarely use them.

ah-HA, that would explain it then. Thanks (again).