on OPEN/CLOSE
The on OPEN and on CLOSE events trigger for various events relating to the opening and closing of a window of different types of windows. In the case of dcc sessions, they trigger when a dcc connection has opened or closed.
Format: on <level>:OPEN|CLOSE:<?|@|=|!|*>:<matchtext>:<commands>
You are missing the "<matchtext>" parameter
/help on open
gemeau50