I have another problem with my mobile now. I ve installed Opera 10.1 in my N8.
Frequently While drafting a mail or posting something, Opera just closes for no reason at all. In fact in the duration of this post, It closed 4 different times and now i am using my PC to put this particular post.
Are you using the inbuilt N8 keyboard or Opera keyboard? Because there is a bug within the old version of opera that meant that when you start typing with the inbuilt keyboard, the app crashes.
To fix this, download the latest version of Opera.
Many other apps running or many tabs open in Opera itself? It's massively heavy on RAM. I switched to Opera Mini because I was experiencing similar issues on my N with 10.1. All fine now that i'm on mini.