Inventory locations error

Nathan,

when saving a new inventory location this error happens:
Warning: Missing argument 2 for bo_perp_work_center::remove_work_center_location() in /home/perp/public_html/egroupware/perp_manufacturing/inc/class.bo_perp_work_center.inc.php on line 175

Despite of this, the location was saved.

What does it mean?

thanks and regards