I have one of those B2100 laying around in a shelf. No problem at all to download Opera Mini 4.5 from m.opera.com and get it up and running. Loading some pages also worked fine. This particular B2100 is more or less brand new but not used so it doesn´t have a lot of stuff saved on it as sms, images etc.

Sorry boymax, I don´t now how I read today I can see now that you have a Nokia 2610 not a B2100 :).

Nokia 2610 should run Mini 4.5 but I suspect it is on the edge...

I took the old Samsung B2100 and downloaded Opera Mini 4.5 from m.opera.com. Mini 4.5 works just fine :). Try before you run out and buy a new phone! This particular B2100 that I had laying in the shelf doesn´t have a lot of stuff saved on it, it is more or less brand new...

Nokia 6720c? Isn´t that a Symbian?