Hi, fjensen,
well, usually a portable browser is not meant to be made the default
browser - quite on the contrary.
Why not download this current stable 1.5.4
installer?
Then uninstall your prior version, set InternetExplorer as default, restart PC, test: did IE manage to take over from FiFo?
Install 1.5.4, set as default, restart, and you should have better luck this time. If not, come back.
btw, a portable AND dev AND test version as your default? :O
You should not try such a thing again, IMHO.
Cheers
SoerenB
Back again ...