Riding Lawn Mowers

The battery on my tractor has died.  I purchased the battery charger that Husqvarna sells (Battery Charger BC 0.8), however it does not appear to be working.  After I connect the cords to the battery and plug it in, the power indicator light turns on and remains a steady light for about 2 minutes.  However, after that the power indicator light starts flashing.  The fault light does not turn on and it never makes it to steps 1 thru 6.  Is there something that I'm doing wrong?  I've tried this 3 times now and it's always the same result.  I also left the charger plugged in overnight and it did not charge at all.  Thanks in advance for your help!