FFP under Win98 does not recognize FirefoxPortable.ini

I have a strange problem with FFP under Win98:

I renamed the launcher to Game2Go.exe, and also the executable in App/firefox from firefox.exe to FirefoxPortable.exe. In accordance to this I changed also the FirefoxPortable.ini which sits in the same directory as Game2Go.exe (=FirefoxPortable.exe) to that:
[FirefoxPortable]
FirefoxDirectory=App\firefox
ProfileDirectory=Data\profile
PluginsDirectory=Data\plugins
SettingsDirectory=Data\settings
FirefoxExecutable=FirefoxPortable.exe
AdditionalParameters=
LocalHomepage=htdocs\index.html
DisableSplashScreen=false
DisableIntelligentStart=false
AllowMultipleInstances=false
SkipChromeFix=false
SkipCompregFix=false
WaitForFirefox=false
RunLocally=true

Under Win XP it runs perfect for all my different sticks and opens the correct locally stored page under htdocs\ ... but under Win98 I always get the error that firefox.exe could not be found.

By renaming everything to standard it opens with an empty page complaining for a wrong missing location file /F:/htdocs/index.html (it should be e: on this PC!) ...
very strange.

It looks alike that the executable is used from the PC but with the local USB setup but not accepting the right homepage ... this F:/... can only be found in Data/Profile/prefs.js as one liner
user_pref("browser.startup.homepage", "file:///F:\\FirefoxPortable/htdocs\\index.html");
but I've read that I must not touch this file.

Nevertheless, by removing this entry from prefs.js, it starts with the default Firefox HP ... and as soon as I rename the .exe and change the .ini accordingly I get the error firefox.exe not found again ...

What do I wrong under Win98 (still using it, maybe a fault ... but I have to for some reason...)

Thanks for any hint, Andreas