When I run qdec, it showed me error message, any suggestins?

 qdec

X Error of failed request:  BadValue (integer parameter out of range for operation)

  Major opcode of failed request:  154 (GLX)

  Minor opcode of failed request:  3 (X_GLXCreateContext)

  Value in failed request:  0x0

  Serial number of failed request:  1571

  Current serial number in output stream:  1572

Thanks in advance,

Yawu