Problem in Extrude command in Creo 2.0

Problem1-> Why cant creo extrude the closed loop in any of the three surface...i dont find any pblem why its should not extrude in the above part.

Problem2-> Now, if i sketch in the other plane and extrude towards the solid creo shows an weird logic for solid modelling....i mean if the distance is less than 20 solid extrudes...if its greater than 20 solid extrudes.....but why it fails if extrude distance is same as the width i.e 20....:((((((
CAN ANYONE EXPLAIN WHY CREO IS BEHAVING IN SUCH A WAY ?

