@mr_500
Sounds like my problem, I was getting a lot of 8000 000D gurus even with Installer. Nothing was very consistent however, until I finally gambled on the cpu...and hopefully have cured it...so far so good.
You probably tried this but....
Try deleting your cache, cookies and delete your global history. If you have the preferences set to a limited amount of space, say 2MB, you probably filled the cache and that I believe can cause a program crash. You could try tinkering around with preferences with the amount of memory you afford graphics, cache size, chip ram limits, etc.
Then again, maybe it's a problem with the 68EC020. I noticed that the 68EC030 doesn't have all of the pins that the full version 68030 has. I don't know if Ibrowse was tested on EC chip versions, though I suspect it should run on a bog standard A1200 with fast ram. In any case, since the EC chip versions of the 020 and 030 are el cheapo plastic packs, shelf life is probably limited....well, ten years of fairly heavy use is asking a lot of such a cheap chip. I've heard of them going on A1200s. I hope this isn't your problem; maybe there is a way you can run a diagnostic on the 68EC020. If it is bad, you could have a surface mount replacement done on that board, maybe even put a plcc socket for future replacement. There is an A.org member (hppacito?) who bought a whole mess of these chips to make a new accelerator. Maybe he'd sell one to you???