When using the Rook in my last game, I noticed that when in Battle, he would completely ignore my movement commands.
If he was not engaged in battle, he would respond to my right-mouse clicks and move to the location I specified.
I died three times in a row because the Rook would continue attacking when I told him to retreat and then quit to file this bug report.
Probably unrelated to my system, but:
OS: WinXP Pro
Video Card: 8800 GTS 320MB
Proc: Intel E6750