As of 2010, 'dev/apr' freebsd port has been changed to 'dev/apr1'. More details in /usr/ports/UPDATING.
# less +/20100518 /usr/ports/UPDATING
20100518:
AFFECTS: users of devel/apr0, devel/apr1, www/apache20, www/apache22
AUTHOR:
pgollucci@FreeBSD.org devel/apr port has been renamed to devel/apr1.
WITH_APR_FROM_PORTS=yes for www/apache22 has been dissolved and may be
removed from your configuration files; devel/apr1 is always used now.
Please manually delete apache-2.\* if installed _before_ updating using
either portmaster or portupgrade:
pkg_delete -f apache-2.\*
Then, if you use portmaster:
portmaster -o devel/apr1 devel/apr
If you use portupgrade:
portupgrade -f -o devel/apr1 devel/apr
Finally, reinstall Apache port if you deleted it earlier and update ports as
usual (`XX' below is either 20 or 22):
portinstall www/apacheXX