Madeinstein,
The amp you are using is a home theatre receiver are you sure it has 4 output channels for the front speakers ? It may have front left and right, and rear left and right ? To Bi-Amp you need 2 front left outputs and 2 front right outputs - else all you can do is Bi-Wire your speakers.
To Bi-Wire your speakers you connect 2 cables from your front left - both go to the left speaker. Likewise for the Right.
At each speaker you then have a choice - I said 1 cable to treble and mid, and 1 to bass. Andrew said 1 to treble, and 1 to mid/bass. Either way connect I speaker cable (red lead to treble(+) and black to treble(-). Connect the other lead to red Bass(+) and black Bass(-).
In my case you now have to remove the metal strap links between the mid and bass terminals. In Andrew's case you would remove the links between the treble and mid terminals. The links are shown below:
Again I think you may be using your speaker terminals on your amp incorrectly, but since I don't know that model I'm not sure.
Crossover: Multi-element medium-order, at 150 Hz and 3 kHz. Tweeter has four components in a 3rd order filter at 3 kHz crossover, using film-caps throughout and a metal oxide resistor.
Terminal Panel: Tri-wirable. Can be single or double wired by removing shorting links provided.