Trouble upgrading math/fftw3 on 6.4-STABLE

[Clint Olsen]

I got this message:

===>    Verifying install for gfortran43 in /usr/ports/lang/gcc43
Making GCC 4.3.4.20090524 for FreeBSD 6.4  target=i386-portbld-freebsd6.4
You need to increase the datasize limit to at least 700000 (and set
kern.maxdsiz="734003200" in /boot/loader.conf) to build with Java
support.
*** Error code 1


Ok, so I added the appropriate flag to /boot/loader.conf, however I wanted
to use sysctl to update the parameter without booting.  However, even
though the parameter is listed in /boot/defaults/loader.conf, sysctl won't
accept this:

# sysctl kern.maxdsiz 734003200
sysctl: unknown oid 'kern.maxdsiz'o

Is there a way to change this w/o rebooting?  Am I even using sysctl
correctly?

Thanks,

-Clint