Description
When you change the SignalTap® II advanced trigger parameter for the state counter to zero, the Quartus® II software version 5.1 may crash. This error occurs because '0' (zero) is not a valid value for the event counter block.
This problem has been fixed beginning with the Quartus II software version 6.0.
To avoid the crash in version 5.1, do not change the parameter for the state counter to zero.