My Place keeps falling apart...??

Ive worked on my game and its up graphic icons and everything finished people even starting to join, all going well but after some time walls will just fall apart and sometimes explode... Yes im not stupid things iv'e done the basics. To start with i thought someone had exploited or hacked the server so i shut it and went on about my day, a little later i checked back to my place joined and had the same problem. Ive used a few free models here and there but changed them so i don't know if ive got an infection in the place or something else is up.

Thanks if anyone knows whats going on its been really annoying.

Thanks - Chimp

Your parts need to be anchored, which locks them into place so things like this won't happen. To anchor parts, in the view tab you need to enable "Properties". Then, select all the parts in your explorer that are falling apart, and check the "Anchored" box in the properties section. This should fix your problem.