Remember, the smaller the number on your extension cord the larger the copper wire.  So a cord designated 12-3 SOOW means it's number 12 wire size (used for longer runs at higher amperage requirements).  It has 3 conductors, white or grey is neutral, black is line voltage and green is ground (green is ground the world round) and is rated for 600 volts.  The 600-volt cords have a much thicker jacket that wears well on the job site but is heavier to carry around.  A cord marked 12-3 SJOOW is called "Junior" rated at 300 volts with a thinner jacket.  It is much easier to carry around but can be easily damaged on the job site.  The SOOW means S=service, OO=oil resistant insulation within the oil resistant jacket, W=water and weather resistance.  

Pay attention to your power cord chart.  Motor starvation will wipe out you Deck Crawler or any other power tool if your power cord isn't big enough to carry the load.  The motor will overheat, crystallize the varnish on the motor windings and short out.  Usually a little puff of smoke signals this event.  The first clue that something is wrong is the heat generated by the tool within the body of the drive motor.  Pay attention to that and you should be okay after confirming your wire size and distance is correct for your tool.  The DDM drive motors are rated at 15 amps so look at the chart, determine how long and what size your extension cord is, and see if you are in the danger zone or not.  A starved motor is easily detected by trained power tool mechanics so the repair cost will most likely be on you rather than the manufacturer under warranty.