Darren thanks for the input but this is a known issue on some cooked roms. It has to do with the manila files that are being used. It was reported in a nother thread here @ppcgeeks. I know cause this has affected me too. I used ssmapa to replace the default calendar as I got tired of trying a million solutions that didn't work. You may want to try Muckys solution in post#32 as it should replace the manila files in question, I haven't tried it myself but someone else reported it works. Hope this helps!
http://forum.ppcgeeks.com/showthread.php?t=47352