I got this code straight from the dbc helper. I hope this helps you!
rem ==========================================
rem DARK BASIC EXAMPLE PROGRAM 6
rem ==========================================
rem This program handles object collision
rem ------------------------------------------
rem Make a wall to collide against
make object plain 2,100.0,100.0
position object 2,0,50,100
rem Load your object
load object "walk.x",1
rem Fix the proper angle for the character
yrotate object 1,180
fix object pivot 1
rem Switch on collision for the object
set object collision on 1
rem Activate manual sync
draw to back
sync on
rem Begin main loop
while mouseclick()=0
rem Clear screen for ink flash
cls
print screen fps()
rem Store old position
oldx#=x#
oldz#=z#
oldangle#=angle#
rem Control variables with the cursor keys
if upkey()=1 then x#=newxvalue(x#, angle#, 4.0) : z#=newzvalue(z#, angle#, 4.0)
if downkey()=1 then x#=newxvalue(x#, angle#, -4.0) : z#=newzvalue(z#, angle#, -4.0)
if leftkey()=1 then angle#=wrapvalue(angle#-10)
if rightkey()=1 then angle#=wrapvalue(angle#+10)
rem Switch between sphere and box area for collision check
if inkey$()="s"
set object collision to spheres 1
endif
if inkey$()="b"
set object collision to boxes 1
endif
if inkey$()="p"
set object collision to polygons 1
endif
if inkey$()="o" then set global collision on
if inkey$()="f" then set global collision off
rem Update object position and rotation
position object 1,x#,0,z#
rotate object 1,0,angle#,0
rem On initial contact, flash screen color
if object hit(1,0)>0
ink 0,rgb(255,255,255)
else
ink rgb(255,255,255),0
endif
rem If collision, restore old position
if object collision(1,0)>0
x#=oldx#
z#=oldz#
angle#=oldangle#
endif
rem Update Screen
sync
rem End main loop
endwhile
rem Switch off collision for the object
set object collision off 1
