The Boston board reported problems logging in to Date-Check.  Here is a workaround that worked for me:

I tried to log in to www.date-check.com in the usual way and got the error message page.
 
I opened a new tab (or window) and went to www.date-check.com again.  
I hit "I Agree" and got the main page of ads.  
I hit "Member Area" (top right) and I was in, without being prompted for name or password.
 
I have done that twice (2 for 2), so I think the first login works but it's not loading the proper page.  Once logged in, take another route to the Main Page and you're in!
 
BUT THEY SHOULD STILL FIX IT!  (Anybody sending an email?

Another method: When I log in and get the error page, I just refresh the page and I get to the Members Control Panel. This didn't work yesterday but has worked since this morning.

I sent them a message yesterday, haven't gotten a reply.

That has worked for me.I did send an email to date-check but it bounced back.
I wouldn't expect a response from date-check customer service right away anyways their customer service is not great and takes awhile to respond.

Logging in with no problems since yesterday.