Tharizdun said:I just looked it up, and if the terrain hampers movement, you cannot take a five foot step.
"In some situations, your movement may be so hampered that you don't have sufficient speed even to move 5 feet (1square). In such a case, you may use a full round action to move 5 feet ...." and it goes on t say that this provokes an attack of oppertunity
"You can't charge or run through any square that would hamper your movement"