Sumo Bot Fully Assembled (with issues)

After a lot of frustrating hours, I have my first Sumo Bot somewhat up and running... unfortunately, he is currently running in circles  I have not found my error yet, but I must have an short somewhere....

Here is the functionality which I do have. (The following four digits control the drive direction, for example, to drive forward, the command is 1010.  To 'turn on a dime' the command is 1001 for counter clockwise or 0110 for the clockwise direction.)
1000 = Right side drives forward (which is what should happen)
0100 = Nothing happens, but both pins on the right side are high (should drive right side in reverse)
0010 = Both sides drive forward (should only drive left side forward)
0001 = Both sides drive in reverse (should only drive left side in reverse)

Although he isn't working, he sure looks pretty.

Completed Sumo Bot Isometric View

Side View

Front View