I have a suspicion that it might be related to one of the Hijack versions. Were you running Hijack?

(Mark, jump in here and slap me if I'm wrong about it).

Re-installing an Upgrade will not fix the config.ini file, as the upgrade deliberately does not touch config.ini.

To fix config.ini, use this procedure from the FAQ to edit it and see if all is well afterwards. Let us know how it goes.