In the 'PORTABLEFIREFOX.INI CONFIGURATION' section, the example .ini reads:
[PortableFirefox]
FirefoxDirectory=App\firefox
ProfileDrectory=Data\profile
PluginsDirectory=Data\plugins
UserProfileDirectory=Data\userprofile
AdditionalParameters=
AllowMultipleInstances=false
SkipChromeFix=false
SkipCompregFix=false
WaitForFirefox=false
FirefoxExecutable=firefox.exe
DisableSplashScreen=false
LocalHomepage=
therefore anyone copy and pasting from the readme.txt to a PortableFirefox.ini file to change any of the settings, like disable the splash screen.. their settings wont work, as i discovered!
sorry if this has already been fixed/reported.