The camera isn't stuck on the ground. What makes you think it is?
It's stuck a short distance above the ground which is what you should expect from the automatic collision function according to the help file. What isn't clear to me is why it gets stuck at the particular distance of 5.45 units (see code snippet at end).

Perhaps it's something to do with the default collision objects that DBPro uses behind the scenes?
sync on: sync rate 60
make camera 1
set current camera 1
automatic camera collision 1,1.5,0
make object box 1,1000,1,1000 `I,err... borrowed this. XD
make object sphere 2,30:color object 2,rgb(255,0,0)
make object sphere 3,30:position object 3,0,1,0:scale object 3,100,3,100:color object 3,rgb(0,0,255)
position camera 0,15,-300:position object 2,0,15,0
do
sync
control camera using arrowkeys 1,3,3
position camera camera position x(),camera position y()-0.05,camera position z() ``homemade gravity
text 20, 20, str$(camera position y(),3)
loop