George Garside's answer is probably the best, as this sounds like an application you'd want to delete, and not simply 'remove from spotlight' (as in hiding it).
I've seen instances where a file is stuck in the spotlight search even though it's completely removed from the system. Sometimes this has to do with permissions of a certain folder and how spotlight indexing works.
If this is the case, and the file has already been deleted, it might require a re-indexing of the drive the file is stored on.
Taken from Apple.com:
From the Apple () menu, choose System Preferences. Click Spotlight.
Click the Privacy tab. Drag a folder or an entire volume (your hard
drive) to the list. If prompted for confirmation, click OK. Remove the
item or volume you just added to the list by clicking it and then
clicking the minus ("-") button. Close Spotlight preferences.
Spotlight will re-index the contents of the folder or volume.
However, since the index most likely screwed up due to a permissions error in the first place, it's a good idea to do more than simply re-index, and instead use one of the many good maintenance applications that exist to repair permissions / clean up misc files / and re-index spotlight all in one sweep.
Personally, I use an excellent app called "Maintenance" (also referred to as Mac Maintenance, though I've found another application with that as it's name, that didn't work as well in my experiences).
Here is a link to download if you want to try it.
And Finally (though as I mentioned earlier I don't believe this is your intention) you can actually 'hide' files and certain extensions from the spotlight results on a folder-by-folder level (This feature is often used to keep adult files away from the eyes of children, etc)
choose Apple menu > System Preferences, then click Spotlight. Click
Add (+), then locate the folder You can also drag a folder or disk
from your desktop or the Finder into the list. To remove a folder or
disk from the list, highlight it, then click Remove (-).