Your amp can work, fella. The problem is twofold here, though.
A) DHD amps do not out out anywhere near their rated output. Sadly they just are not quality units and consequently it is the reason you see them most often at those flea-market type clearance sales at your local fairgrounds or in pawn shops. Most reputable dealers refuse to carry them.
B) You bought a 4-channel amp to power a single subwoofer, //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif You can bridge 2 of the 4 channels and wire the sub's voice coil in series to show the amp a 4 Ohm load and it will work but the amount of wattage being given your Solobaric will be less than optimal...