I don't see anything wrong there at all unless there is some sort of weird encoding issue with the string... Are you having the same issue with other filter types such as message text? If so it could be a problem with the install as from the screen shot it looks like its a fairly fresh deployment?
I'd try creating a new rule, no actions against it and just try the filters one after another see what the problem is limited to it should literally be a case of just typing in "192.168.11.207" in your case for a IP based match as the filter is set to simple and the "S" is selected for a sub-string search so nothing more should be needed.
If your having the problem with the other string based filters as well it might be worth logging a support call.