I just upgraded to version 4.1 from v 3.6 but now when I try view a comment from the post I get this error

mysite/mt-comments.cgi?entry_id=24

_{Movable Type
An error occurred
close Invalid request}


I also noticed when I look at the comments on a post there do not seem to be any there ie: (0).

I have rebuilt the pages and comments but this bit seems to not work for me any help would be great.