In the first case, I would recommend either parsing the user input to try and return some reasonable results, or just return a more direct error message.
But they do run on different web servers. The first is a custom Arc-based web service, the latter an Apache install. What could be a more direct error message than stating plainly that the information isn't available?
ERROR: Web server not shown in header.
If I search ycombinator.com, I get:
Apache/2.2.14
In the first case, I would recommend either parsing the user input to try and return some reasonable results, or just return a more direct error message.