I'm in a hurry, so I'm just going to comment on the binding (without checking the code inside the procedure). If you want it to execute every 10 minutes, then this is the proper binding:
Also, you're using [lsearch] to search in a string (which is never recommended), $posting_chans should be a list. Wildcards in [lsearch] can only be used with -glob switch and the wildcards are specified in the third argument (the search string).