I'm going to assume your the developer.From my point of view, there isn't anything to fix, as it is not broken.
It does what it was designed to do.
It does not claim to give you every possible timetable.
The goal of it was really just to make it produce some usable timetables for 3rd/4th year Electrical Engineering and Computer Science students.
If your in first year, or in accounting or whatever, then it was not really written with you in mind.
The fact that it has timetable information for the these other courses is mostly because it was not any extra effort to add the (approx. 2900) extra courses once you have added the first 100.
Having said all that, many people use it thinking that it should just produce something nice for them without much intervention.
The endgame is this: It's a hobby that hasn't been worked on seriously for a year at least.
If anyone out there wants it to improve then they need to contribute. It doesn't write itself. (and there is some seriously low hanging fruit)
Asking for contributions on a closed source project is just :S
Why don't you open source the code so people can see it? If they fix a problem/add a feature, etc. they can email a patch in. Doesn't mean you have to accept it.