are doing batch simulation ?
have u checked the audit option ?
the audit option will let you know that you have assigned the models properly or not?
before doing simulation please check the driver and receiver in the ibis is characterized properly
if an out put pin is configured as input or if a bidirectional pin is configured as input you may get this error which net the error is coming just check the ibis
do audit only and check if the models are proper
It says "no driver", so be sure there is a driver selected. The typical IBIS model for DDR interfaces will use [Model Selector] for you to select among the different transmit impedances and ODT input terminations. Make sure that either the FPGA or memory has a driver, and the other one has a receiver. "Select" which I/O by moving it to the top of the [Model Selector] list.
If you are using batch Mode, you can select round robin and it will flip them for you.