A replacement plug end may be purchased on line. Most parts dealers have them or you can try locally at AquaQualitypools.com. They have a store in Westbury, NY.
Make certain the transformer is or is not working. If yours has a reset button, it must be pushed before checking for voltage at the transformer outlet. Check the fuse too.
The replacement plugs are easy but theres a good chance all you really need is a power cord and aquaqualitypools sells their own brand at a great price. I have one and it works great.
If the original problem was a totally dead robot, then the cure is in the electrical supply...the cord, transformer, or plug end.
UPDATE. On May 11, 2008 I looked at your Aquabot. A continuity check revealed a bad fuse holder in the transformer. A continuity check of the power cord revealed a break. In fact, after digging out the hardened 15-year-old putty from the terminal well, I found both cord ends were corroded and broken as well as 1 wire from the pump. I cut the cord at the handle and crimped new terminal ends to both cord and pump then repacked the well with new putty. I hope to hear about the robots future performance after it's "quadruple bypass".