i just bought an oster prima latte machine. I followed all the instructions, priming it and went to use it and it does not work. The box had never been open so do not know what is wrong. Before i take it back to the store for a replacement can someone suggest what i might be doing wrong. It seems like it wants to work but after about 90 seconds it shuts down. The coffeeporta filter is hot but nothing comes out of the frother either....the porta filter is quite stiff in turning to lock it in place, not sure if this is normal. Can some one help