installworld error rendering machine unusable

running installworld failed when upgrading from SNAP005 to newest -CURRENT,
stops when installing kerberos5 but dont give a description of the error,
after that everything dumps core with signal 11, running installworld
again returns:

Makefile, line 156: warning: "LC_ALL=C date" returned non-zero status

and the machine is completly unusable. Installing on to a diferent
$DESTDIR dont
give any errors.

i followed the exact steps in UPDATING:
make buildworld
make buildkernel KERNCONF=current6
make installkernel KERNCONF=current6

boot -s
fsck -p
mount -u /
mount -a
adjkerntz -i
mergemaster -p
make installworld