First, make sure your fluid is good. The Dynamic Drive is on the same system as the Power Steering, so check that reservoir.
What is your exact error? I had Dynamic Drive failures in the past, the first time ended up being my Steering Angle sensor. The second was the ARS Block as Herb is showing. My last one was a battery. Of course the battery threw a bunch of other errors also.
When it was my steering angle sensor it would pop up while I was driving. The ARS block failure would be at random times, sitting at a light, doing nothing, then BING, here is Dynamic Drive warning.
Lucky for me all these were under warranty (except the battery).