Hello Everyone... I'm in great need of help...

I purchased a factory navigation setup from one of the forum members. It came with the following:

Navigation head unit
GPS Antenna
East/West CDs
Manual

I removed my old head unit, mounted the GPS Antenna, ran the wire and reinstalled the new head unit. I turned on the radio and everything seemed to be just fine. All of the radio features work great. I inserted the navigation CD and it recognized between 6 and 9 satellites. However, when I drove the car, the navigation feature was worthless. Every destination I entered, it would try and take me in the opposite direction. It wouldn't recognize any roads and wouldn't recalculate anything. Also, the compass was never facing the correct direction. For example, I entered my home address as a destination when I was about 3 miles from home. It said "calculating route" and then listed the street that it thought I was traveling on. However, it was not correct, in fact, I was about 4 miles from the road it listed on the display. Then the voice said "turn right in 100 yards." I kept driving all the way home and it never changed. Something isn't right with this, and I'm not sure what it could be. One member told me that he had to install a "speed sensor wire" and a "reverse sensing wire," which I did not do -- maybe that could have something to do with it? Any help, advice or suggestions would be extremely appreciated. Thank you in advance!