create_atoms and atom_style

Hi
have two problems. The first one is the ERROR message: Invalid atom style (atom.cpp:343) by using

atom_style hybrid granular molecular

this message occurs despite that I installed the molecule package.
(I use the LIGGGHTS-PUBLIC Version 2.3.8)

My second probleme appears by using the create_atoms command.

create_atoms 1 single -1 0 2 units box
set atom 1 type 1 diameter ${Durchmesser}
fix gravi all gravity 9.81 vector 0.0 0.0 -1

The particle is inserted and falls down on the ground (gravity) but when it touches the ground it seams that it gains an extra force and bumpes itself out of the simulation box. But whe i use the fix insert/pack command with the same atom type the inserted particles behave normally.

Does someone know how to fix these problems?
Thanks

Cheers, Jürgen