The AC and DC thresholds should be defined in the [Receiver Thresholds] block of the IBIS model. See the IBIS 4.2 specification for details about that.
The second error is telling you that the model you have assigned to the controller pin on the address net is an input type. This model cannot drive the signal from the controller. Your IBIS model is not correct, or you have interactively assigned the wrong model to this pin. The log file tells you where to look to find the problem. The pin 7S00.AD28 has the wrong model. Select the net DDR-AA8 and observe the models assigned to the pins on that net. In the model assignment window you should see green triangles with little letter R next to each pin name. If there is a red ? then the model is not assigned. If the green triangle does not have a R by it then the model is assigned interactively and you should remove the model assignment.