Your problem description is not clear, but I dont read german... BUT
Code:
aufbo=c_move(my,vector(0,0,-6*time_step),vector(0,0,0 ),GLIDE+IGNORE_MODELS);
should be                                      v(a bit)     v(a LOT)
aufbo=c_move(my, vector(0,0,-6*time_step), nullvector, GLIDE|IGNORE_MODELS);
AND each 'part' of an if should have brackets like so
Code:
if(key_b&&jumpen==0)
should be
if((key_b)&&(jumpen==0))

and later on 

if(hohe<18&&aufbo<0.2)
should be
if((hohe<18)&&(aufbo<0.2))
Otherwise odd things can happen.

"There is no fate but what WE make." - CEO Cyberdyne Systems Corp.
A8.30.5 Commercial