Is your battery holding a charge? The following is from a Motorola help forum.
The DROID X handset has a notification light near the top of the phone.
It is used to provide silent notification and gives several colored alerts.
These are the standard ones for DROID X
Blinking Green: You will have a blinking green notification light whenever your screen is off and you have a notification (Email, Text, Voicemail, Missed call) in your notification bar that has not been cleared.
Blue: You can an incoming call.
Red: Your battery is low.
Solid Green: when the battery is low/dead, insert USB/Charging cable will turn on the green LED to show sign of life. The LED will turn off when the battery is charged enough to power up the phone
There are several Marketplace applications available that will turn the notification LED various colors including and beyond the colors on this list depending on the function it is used for. You will need to refer to those marketplace applications for support of their notification light colors.