Unfortunately, but Nintendo's Error Code Lookup can't seem to find the 102-2815 error code, so it can't help explain what the problem might be and/or and suggestions on how to fix this, sorry.
So perhaps you might want to give a call to Nintendo's 1-800-255-3700 (6 am ~ 7 pm Pacific, everyday) Customer Service number, and one of the service representatives can do some over the phone troubleshooting to determine exactly what the problem(s) might be, and then talk you through any needed steps to correct this.