In the CheckPortableAppsSplitDIR: labeled section,
$SETTINGSDIRECTORY never gets set like it does in the rest of sections above it.
Previously mentioned error (test for "..App..", using "..Apps..") seems to be masking this.
Also, Launcher seems to be ignoring the ini file setting for SettingsDirectory.
GIMP asks user to create setting folder in user's home folder on the machine.
Check your comment in the GIMPEnvironment: labeled section.