[ODE] problem with adding forces

[lazareer]

Hi everyone!
I am new on this list, and maybe my question is silly and
the answer is obvious but I will ask it anyway:
I've  got  problem  when  I add force to the body (dBodyAddForce). The
force  is  added  (dBodyGetForce returs correct vector)but it takes no
effects  in  the  simulation  step.  If  there  is no gravity the body
doesn't move. Why? has someone any explanation? maybe someone had such
a problem?
Thanks for any ideas!

P.S.
I was looking in the ode list archives but I found nothing that could
help...

lazareer