Hi,
I'm not sure what is causing this error in your case.
Can you have a look at the "MD Grid" page of the IW FeaturesDemo (included with the TMS IntraWeb Component pack download) to see what you are doing differently?
Can you have a look at the "MD Grid" page of the IW FeaturesDemo (included with the TMS IntraWeb Component pack download) to see what you are doing differently?