Make sure your port honors WRKDIRPREFIX. Most ports do not have to worry about this. In particular, if you are referring to a WRKDIR of another port, note that the correct location is WRKDIRPREFIXPORTSDIR/subdir/name/work not PORTSDIR/subdir/name/work or .CURDIR/../../subdir/name/work or some such.

Also, if you are defining WRKDIR yourself, make sure you prepend ${WRKDIRPREFIX}${.CURDIR} in the front.

For questions about the FreeBSD ports system, e-mail <ports@FreeBSD.org>.
For questions about this documentation, e-mail <doc@FreeBSD.org>.