firefoxportable

I like to run firefox portable out of my usb drive. i installed pandora.jar in my c drive. i run the .bat file and then launch firefox portable and insert the http://localhost and pandoras jar launches and starts playing music. but when i try to grab mp3 files it gives me a error that i am not using firefox. i guess my question is has anybody gotten pandoras jar to work in firefox portable and if they have please post some instructions to do so.