From 40tude Dialog Wiki
A little script posted by Andreas Loch in de.comm.software.40tude-dialog. Sets the ignore flag and jumps to the next unread message. As Andreas suggests, it would probably be a good idea to assign this script to a keyboard shortcut such as "i". Just paste the following into a new custom script and you're ready to go.
Program IgnoreAndSkipToNextUnreadMessage; Begin ADo('Ignore'); ADo('SkipToNextUnreadMessage'); End.