This is a strange problem and just started occuring not long ago for no apparent reason, my comments used to work but one day just stopped!
When anyone tries to submit a comment in either FF or IE it just goes to a blank wp-comments.php page
I have no plugins installed and does not work in the default theme either. I upgraded to 1.5.1 and this did not fix it either.
The address of my wp install is http://randomo.ocel.co.uk if anyone wants to test it out for themselves.
I appreciate any help anyone has to offer.