GIMP Portable 2.8.22 and earlier incorrectly set the default font path for the PortableApps.com Platform to \PortableApps\Data\fonts instead of \PortableApps\PortableApps.com\Data\fonts. The gimprc file within DefaultData should read as follows:
# GIMP gimprc # # This is your personal gimprc file. Any variable defined in this file takes # precedence over the value defined in the system-wide gimprc: # ..\GIMPPortable\App\gimp\etc\gimp\2.0\gimprc # Most values can be set within GIMP by changing some options in the # Preferences dialog. (font-path "(INITIALGIMPDATADIRECTORY)\\.gimp\\fonts;(INITIALPORTABLEAPPSDIRECTORY)\\PortableApps.com\\Data\\Fonts") # end of gimprc
I'll have this fixed in the next release and possibly add in some custom installer code to fix the path for any existing users as well.
Any users wishing to get this working now can manually edit the gimprc file within Data to add in the \\PortableApps.com between \\PortableApps and \\Data.
This is fixed in 2.10.0 released today. Existing users can manually add the directory or reset their GIMP Portable settings by deleting the GIMPPortable\Data directory.
Sometimes, the impossible can become possible, if you're awesome!