Don't know if you can correct it. In my first game there was a magic crystal in an underground area that just could not be clicked on, so I suspect there is a slight problem with the interface. On a side note, I occasionally get enemies on the adventure map run towards me and straight past without attacking. Weird.
About the truth arena, you fight yourself, as in, an exact doppelganger of the stacks you have. You have to have used up your full leadership potential I believe. Anyway, the fight is easy because your hero gives your own troops improved attack/defense etc, plus you have spells/ragebox. I think you get 3 of each rune as reward.
You can fight in the arena again later, although at first I was told that I wasn't strong enough. The second fight is against DOUBLE your stacks. This is probably doable but I couldn't be bothered having to rebuild my stacks again, so I left it. I think I read somewhere that you get 10 of each rune for completing this but I'm not sure.
So in summary you aren't missing a great deal unless you desperately need the runes.
