Try selecting "no" in the "exclude bad websites" category. Also try selecting no city. You may come up with multiple ladies with the same name . You will have to weed through to see if the lady you are looking for is among them.

Search for part of the URL, ideally a part that is probably going to be unique for that lady.  For example, here's the URL for a randomly-chosen ad on Eros-DC:

http://www.eros-dc.com/files/dc-ryan19-jeanine1.htm

If I didn't have any luck searching for "Jeanine" or on her phone number, I might try searching the DC message board for the string "dc-ryan".  If I had reason to suspect that she had been discussed somewhere else, I might try searching on that message board for "ryan19" as well, since she would have presumably placed an ad in that city's Eros section.

It's a low percentage game.  Odds are that if you don't get a hit on the name, phone number, or email address (after selecting "allow bad websites" and "allow bad phone numbers"), you probably are out of luck... but it's certainly worth a shot.

One other tip -- if the lady's ad uses a non-local area code, try searching the reviews database for the city that matches up with that area code.

I can recall having the same difficulty with Eros, and that is because many of the ladies who use that as source of information tend to change cites, locations and info becomes inaccurate.
That is one reason City Vibe is probably a better source than Eros - my personal opinion, nothing more is that Eros also tends to lend itself better to LE postings.