Dude.  What may have happened here is that the pads didn't back off the disk when you lifted your foot off the brake.  The oil then heats up and expands forcing the pads on even harder until you ride over a lose surface and the wheel locks up. 


You have probably had the caliper sorted by now, but just a word of warning.  If you removed the caliper bolts it is vital that they are replaced using "Thread Lock"  (it's that blue gum you find on the treads of critical bolts when you remove them for the first time). It is common for the caliper bolts to vibrate loose and fall out. The caliper then bounces on the road until it jams between the swing arm and the rear wheel, then you will need new jeans!