secondary air injection system

seven months ago i bought USED 2000 JETTA , today the check engine light came on. i went to auto zone where they checked the obd code, which said "number crossed: p0411, the pcm has determined that the flow detected in the secondary air injection system is incorrect for the current engine operating conditions." the people at auto zone did not know what that meant and they did not have a maintenance book to sell me. what does that message mean?

secondary air injection pump failure can give you 0411 -also MAF sensor