Splitting based on month/year

Hiya all.. 

I am trying to archive all my email for a hundred or so 
email lists I archive into seperate files based on month
and year. I am having some problems though. When running against
a mbox file I get messages like:

procmail: Skipped "Dec 21 20:53:14 1999"
procmail: Skipped "Dec 23 01:26:47 1999"
procmail: Skipped "Jan 8 14:04:51 2000"
procmail: Skipped "Jan 13 09:32:16 2000"
procmail: Skipped "Jan 19 16:01:27 2000"
procmail: Skipped "Jan 26 16:09:30 2000"
procmail: Skipped "Jan 31 15:45:27 2000"
procmail: Skipped "Feb 2 09:57:09 2000"

Looks like one line per email in the file. Nothing is showing up
in the appropriate files.
 
What am i doing wrong? I am kinda new to all this procmail 
so go easy on me.. I looked over the FAQ but couldnt figure out
what was wrong. Also since my .procmailrc is huge already just matching
list addresses is there a way I can put this recepie into a function or
something or another file and include it in each mailing list recepie
without having to have the same dozen lines over and over in the
.procmailrc for each mailing list? I hope to use these seperate split up
mail files to archive out to mhonarc. 

Thanks.. Mike

   :0
   * ^*sun-managers
   {
      :0
      * ^From [^ ]+  \/.+
      FROM_=$MATCH
      :0
      * FROM_ ?? ^^... \/[a-z][a-z][a-z]
      { MONTH=$MATCH }   
      :0
      * FROM_ ?? ()\/[1-2][0-9][0-9][0-9]
      { YEAR=$MATCH }
      :0:
      sun-managers/$MONTH$YEAR
   }

   #....Many other email lists with the exact same recepie.

   :0:
   $DIR/Unknown