Darkstar_FX_20040504_SSE build, Windows Xp Home SP1 up to date.
After installing in a fresh folder but with the old profile, Firefox got stuck on "Installing extensions...." which had to be X'ed. Once this over, program started with no problems. All old extensions were listed but could not be uninstalled.
Deleted the profile and restarted Firefox.
Tried to install Adblock (2004-01-12) with the new profile but it will not install.