Hello,
This is Pixy2 trying to execute an older command from Pixy1. You must have installed Pixymon2 over Pixymon. To get rid of the error bring up the Pixymon tab
https://docs.pixycam.com/wiki/doku.php?id=wiki:v2:pixymon_index#pixymon-parameters-tab
and delete the command in the “Pixy start command” field.
Hope this helps.
Edward