[CentOS] dhcp annoyances

Well, googling has failed me. We've got a pxeboot setup, but we keep
getting, in the logs,
parse_option_buffer: malformed option dhcp.bootfile-name (code 67): option
length exceeds option buffer length. This is CentOS 6.2

The section for those machines that can pxeboot is:
group {
        allow booting;
        allow bootp;
        filename "pxelinux.0";
        option dhcp.bootfile-name "pxelinux.0"; (I added this, based on
something I found googling)
        option subnet-mask 255.255.254.0;
        option routers  <our subnet elided>;
        default-lease-time 172800; # 2 days.
        max-lease-time 432000; # 5 days.
        next-server vessel.cit.nih.gov;
#BOOT THESE

I see the entries for option-128 and option-129, but those, based on still
more googling, seem to actually be for etherboot, not pxeboot.

So, does anyone have any idea where this buffer length is defined?

       mark, one of whose goals is less garbage in the logs