As far as selecting a position, did you mean a section or area?

At the bottom of RB is a From-Thru setting you can use to select an area, or you can simply highlight it in the Tracks window by dragging the mouse over it. You can do the same thing in the Audio Edit window, but only for a single track.

And by freezing, did you mean stuttering or skipping?
Were you doing anything else at the time?
And as Chantelle mentioned, you may get better response if this was in the Realband forum. Maybe a Moderator can move it there and link to it from here (?)

Make your sound your own!
.. I do not work here, but the benefits are still awesome