This template have nothing special as plugin or component.
My testing:
Explorer 8 on windows xp
1— Clear cache, cookies and all...
2 — Load any page with comments without the rss choice
No complaint, no errors
3— Clear cache, cookies and all...
4 — Load any page with comments with the rss choice
Same error...
I will leave the rss button for a while for you to test
I reinstall completly Joom comments and try to use an original templates provided with your components. Same problem...
For what reason the error say mozilla, I don’t know ! This is explorer giving that error and I’m not suprised it can’t recognize itself...