Hotpoint Ultima WMD940 won't wash?

Hi, the problem we have is that the machine will fill with water twice & then it stops, the drum won't rotate & after a few minute an error message showing F:01 with appear & the machine emptys again. You the have to turn the machine off at the mains & after waiting a few minutes & switching back on the same thing will happen. We have tried stopping the machine from its cycle after it fills & switching off at the mains again, then retrying which sometimes works, but more than often it will just fill with even more water & still not rotate. It does go through a little spell of working fine for a few days & then this problem again.
Please help if possible!
Mark.