Whenever I start up the creation kit and load up the skyrim file it gives me like 10 errors, it seems to be saying there's objects missing, and also says something about the navmesh... and when I open certain parts in the creation kit it crashes it... Does this happen to more people or is it just me?

These can be ignored, just hit yes to all.

The kit still crashes when I click ok when making a quest and at some other points too though...

There ARE some errors that make it crash. Some things in the CK do not work, or work as they should .