Yeah, its prob got an issue- Back it up ASAP.
From
Self-Monitoring Analysis and Reporting Technology (SMART)
If you experience a SMART alert using your drive, you should immediately stop using it and contact your drive manufacturer's technical support department for instructions. Some companies consider a SMART alert sufficient evidence that the drive is bad, and will immediately issue an RMA for its replacement; others require other steps to be performed, such as running diagnostic software on the drive. In no event should you ignore the alert. Sometimes I see people asking others "how they can turn off those annoying SMART messages" on their PCs. Doing that is, well, like putting electrical tape over your car's oil pressure light so it won't bother you while you're driving!