ahhhh, well spotted joshpet!
i had php/doexpire.pl
no such thing!
so i've amended it to php/doexpire.php
and guess what, it wont bloody install!

i'm now completley stumped.
This is what is in my cronjobs file
[] 0 2 * * * /usr/local/etc/httpd/htdocs/ubbthreads/cron/php/doexpire.php
0 1 * * * /usr/local/bin/vnukelog [/]
and this is the error message i'm getting from telnet
[] "cronjobs":3: bad day-of-month
crontab: errors in crontab file, can't install[/]
wtf??
