e4 message and leaking machine?

Help! I have been getting the e4 message I have followed all of the suggestions but still the machine will not do a cycle, it starts and goes for about a minute and then the error comes up and there is more water coming out of the bottom, i have checked the machine for leaks and what i can see is that the bit that the upper locking nut screws onto looks as though it is broken and this does not close correctly, could this be the reason for the problem and would we be able to buy this part as a spare i can only see the locking nuts online not the bit that it screws into. Please help as i cant afford to replace the machine just now :(