I\'m using the following NSIS script:
Name \"My app wrapper\" Outfile \"MyAppSetup.exe\" InstallDir $TEMP\\MyApp\\Install Function .onInit SetSilent silent Funct
I don't know if it would solve your problem but I would write :
Exec $TEMP\MyApp\Instal\setup.exe
Are you sure that $TEMP is pointing to C:/Temp? Did you check it?