I'm running 6.0.2. There have been some necessary updates since 6.0 so you might check the updates again. As some have stated, version 3.6 of firefox worked a lot better than 6.0 but I'm using 6.0.2 now and it seems to be better than 6.0.
So some recommendations are either upgrade to 6.0.2 or downgrade to 3.6 IMO. Or, try Chrome. I never recommend IE, but to each his own. I still have it installed and used on occasion.
I'm running 6.0.2 and am having no issues with INGO. However, I have run into some issues on other sites, including the Indy Star. Nothing major though.