StickWiki issue, maybe Java issue after 3.5.7 --> 3.6 upgrade

Very strange issue I'm having at home. I use Wiki on a Stick (aka StickWiki), a single XHTML file that contains a basic wiki (no history, single user) that I use for various purposes. My novel, but also a dining blog I'm trying to get off the ground, and miscellaneous stuff.

Anyway, normally the thing works fine. I have three copies of Firefox Portable 3.5.7 that I upgraded to 3.6. Mine at home, my wife's at home, and mine on the flash drive. The two at home can't save changes to StickWiki following the upgrade. First, it asks me if I want to grant StickWiki permission to edit a file on my device, which I always grant it.* However, at home, a message comes up saying that Java can't write to the device. I went to the Java site and installed the latest Java, and it still wouldn't do it. Works fine on the flash drive, though.

The flash drive only gets used at work on a Windows XP Pro SP2 computer and the two portables at home are under Windows 7 Home Premium. Not sure if that matters though.

*Is there any way in about:config, e.g., to make it never ask me this again, i.e. to remember the answer I give once?