Also, I do not believe you were running Dirty Trick correctly.
I think i works like this:
normal: attempt combat maneuver, which provokes attack of opportunity. if successful, impose one of the listed conditions for 1 round, + 1 round for every 5 points the check beat the target's defense. At this point, the effect goes away on its own, without requiring any action on the victim's part, which is why the effect has a duration listed (why else would it have a duration, unless it goes away on is own?). Alternatively, the target may remove the condition with a move action spent prior to the listed duration.
I'm pretty sure it works this way, otherwise the Dirty Trick maneuver gets very silly. Compare it to being Tripped, Grappled, or Disarmed - Dirty Trick lets a character do a wide variety of different things with a single kind of maneuver, but none of them last as long or are as difficult to overcome as the more specialized tactics.
There are two feats one can take to improve the effectiveness of the tactic:
Improved Dirty Trick feat: As above, but does not provoke an attack of opportunity; you get a +2 bonus on dirty tricks, and a +2 to resist dirty tricks. This feat requires Int 13 and Combat Expertise.
Greater Dirty Trick feat: as above, plus you get an additional +2 bonus on Dirty Trick (stacks with Improved) and an additional +2 to resist Dirty Trick (stacks with improved). Also, the Trick lasts 1d4 rounds base, rather than 1 round base, and removing it early takes a standard action, rather than a move action. This feat requires int 13, Improved Dirty Trick, Combat Expertise, and a Base Attack Bonus of +6.