I use K-Meleon because the portableFirefox didn't run on USB-stick if it is installed in the system, too (then the preferences of the system were used, what I didn't want).
So K-Meleon is very nice and has only one "bug" that it save his configuration with drive name...
I manually deleted the drive letter from the ini files and it work good.
Could you change this behavior, surely with a plugin rather than as standard configuration? Thanks.