I am looking in the SunbirdPortable.nsi and i think there is a problem in it.
At line 117, we have
ReadEnvStr $APPDATAPATH "APPDATA"
And, after that, on line 198, there is something like this
IfFileExists "$APPDATA\Mozilla\Sunbird\*.*" CheckIfRunning
Assuming the syntax of ReadEnvStr
the Environment variable will be stored into $APPDATAPATH variable
So the line 198 (and some others near line 383) would be
IfFileExists "$APPDATAPATH\Mozilla\Sunbird\*.*" CheckIfRunning
No ?? Is this correct for you ??
Correct me if i'm wrong.