i want to creat a robot with a sonar sensor, not the pioneer2dx one. the code written just moves the pioneer robot and scans the enviornment.  how can i create one of mine? i tried the code and got this error message.
 
Parsing Configuration file "diff.cfg"
PLAYERPATH:/usr/local/lib/libstage...stage
invoking player_driver_init()...success
stage driver 6665.31.0 => "diff.world"
[Include pioneer.inc][Include map.inc]
err : diff.world : 97 : syntax error2 (world file.cc Parse TokenWord)
err : Unknown Model type "World". Model has not been reated.
(world.c stg_world_create_from_file) done