Perhaps I can help, ...I hope. The first thing I see, is that you set the lpc to a higher than default level before scanning the journal. I believe that for the journal to find anything, you'll have to give it enough time to react to any actions your client is sending to the server, and time for the client to respond. So perhaps putting in a little 'Wait 5' or 'Wait 3' after the ScanJournal %JINDEX will help to insure that the sub will have the time needed to read and react accordingly. I also think that you should have the lines "ScanJournal %JINDEX" and "set %JINDEX #JINDEX + 1" switched. I may be wrong on that one, but it looks 'off' to me.
Regarding your usage of return #false/#true, it's completely up to you how you want to respond to those values. Your usage is correct in that if you find that the journal entry IS in there, you return a #true value, and you evaluate what to do in the sub from which it came, and vice versa.