I had the same problem one time after doing a burnout riding the breaks. It eventually went off, but had me wondering. Sorry I can't help, just thought I'd add.
I think its just the abs sensor. Mine has been up for a year or more. It's pretty common for them to go out after doing a gear install (that's when it happened to me) because they have to remove it to do the install. So basically you just wont have anti lock brakes anymore. Since the sensor is out it has no way of telling when you lock up the brakes.