Last year I installed "Low Grav Racer" on my JB 3G & for some reason it just would not load completely.
I even spent a few days emailing back & forth with the developers of Low Grav & they were stumped. It seems I was the only person that was having this problem.
It was suggested that there could be a conflict between apps that was the cause, so I started deleting apps that I wasn't using, which were quite a few actually.
I never knew which app or apps were the problem since I deleted apps in a group rather than 1 at a time.
But afterward, the app in question did start up properly & ran just fine.
So I would have to say that yes, there could be a conflict causing your new app to not load.