E17 doesn't work with compiz as it is. You need the "hacked" version of compiz (ecomp/ecomorph) to make it work. I'm not sure if there is a simple way to install ecomorph and ecomp onto the non-compiz version of Elive.
The easiest way is to re-install your system using the ecomp/ecomorph version of elive (called elive-compiz).