Code:
# portmaster php5-pcre
[...]
===>>> The following actions were performed:
Upgrade of libtool-1.5.24 to libtool-1.5.26
Upgrade of gettext-0.16.1_3 to gettext-0.17_1
Upgrade of gmake-3.81_2 to gmake-3.81_3
Upgrade of pkg-config-0.22_1 to pkg-config-0.23_1
Upgrade of libxml2-2.6.31 to libxml2-2.6.32
Upgrade of php5-5.2.5_1 to php5-5.2.6
Upgrade of php5-pcre-5.2.5_1 to php5-pcre-5.2.6
Worked for me. Have you tried updating the ports tree, cleaning work dir and rebuilding the port?