Well, it is still listed in Google, and possibly others:
https://encrypted.google.com/search?q=inurl%3A%2Feuhsd%2Fshow.php
Those hitting it are probably individuals/bots/botnets who look for signs of infected sites on search engines and try to get in your server. But since everything 404s you shouldn't have anything to worry about.
Some bots (quite a lot actually) also just try common malware paths on random sites BTW. If you try a massive load a day you'll get lucky sooner or later
.
EDIT:
All those 157.* ones are legit Microsoft IPs BTW, MSN/Bing bots trying to index your site.
(it kinda annoys me how long and often search engines keep hammering 404 URLs these days... in the same kind of situation with a site of mine and google)
/ 
