Make sure you are selecting the model in 'object' mode...not faces or verts, (as far as I can remember LOL). So highlight the object...RMB and select 'object' then 'CTRL D' to duplicate...then'w' to move it away from the original. You can then just press 'SHIFT d' to duplicate as many as you want.
cheers bullet
bullet1968
"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes