Some apps not working

I have a motorola droid and the 3D gallery just stopped working for no reason. every time I want to look at my pictures, a window pops up that says the app has stopped working and i have to force close it. A few days after that, my wallpapers stopped working too. I cannot access the wallpaper gallery at all...its just stuck on one of the non-live backgrounds I had a long time ago. Also, some of the other apps screw up sometimes for no reason. like when i want to open text messaging, it takes me to maps. my phone just does a bunch of random bullsh*t all the time. can anybody tell me how to fix these problems? thanks