Battery problem???

Tonight I got the low battery warning below. Since my battery said it was full, I just "clicked" it off. Later I shut the top (putting the computer into sleep mode). When I opened the top up about 2 hours later, the computer appeared to be dead even though it was plugged into the charger. After hitting "enter" several times, I did a reboot by holding down the power button. It took several minutes to come back up and when it did, I got the "low battery warning" again, even though the gauge said full at the top of the screen. If it makes any difference, my MB is a '08 S.R. model.

According to the data below, the battery seems to show normal status. Anyone know why I would get this warning twice with a full or nearly full battery AND plugged into the charger with a steady green light. The computer and battery are 13 months old.

[Battery Stutus| ]