Lost monitoring of switch ports

I -WAS- using OpManager to gather traffic data for my Dell PowerConnect 5224 switch. I added the device and all was well. I then went into "configure ports" and turned off ports that I did not want to manage. All was fine. I later went into "configure ports" and turned a few ports back on, while still leaving several turned off. Once I did this, the "interfaces" section showed ALL ports, with stats of N/A. Now if I go into "configure ports", the list is EMPTY. I have tried removing and re-adding the device, no luck. Snapshot shows all interfaces, "configure ports" list is empty and map view of switch shows no ports.

James