Reef octopus extreme 200 pump seized

I shut down my skimmer with a psk-1000 pump (serial number 4000780) using apex fusion to perform a water change. When I tried to start it back up the impeller would not rotate. The skimmer has only been running for 3 months, purchased 1/1/14 from Marine Depot, tank started up in March. I took the pump apart to make sure it was clean and there was very little "crud" on it but i cleaned it off anyway. The impeller will rotate with the end cap off (briefly plugged it in to avoid damage). The orange rubber piece in the end cap seems to be holding the impeller from spinning. Any help would be greatly appreciated.