Updating from 9.1-release to svn head: what might be the problem?

Hi there,

I've been trying to install fresh -CURRENT (in VirtualBox/i386), and since
recent snapshots did not work for me, had to do this by first installing
from 9.1-release .iso.  After "svn co .../head /usr/src" and standard make
world/kernel/mergemaster procedure (w/out any custom settings in make.conf
or src.conf), I apparently keep getting screwed up system (repeated twice
from scratch already):

  1) mtree is complaining that BSD.usr.dist's line 1150 is too long (wtf?)
  2) trying to do 'wc -l .../BSD.usr.dist' results in immediate segfault
     (wc -l /etc/passwd works though)
  3) installing anything from ports fails due to "checksum mismatch" of
     pkg-1.0.13.tar.xz distfile, while checksums actually match if verified
     manually (wtf?)

Am I doing something wrong, or perhaps missed some vital UPDATING note?

Thanks.

./danfe