unable to update pkgsrc from 1.6.2

[Jan-Hinrich Fessel <oskar%fessel.org@localhost>]

I did the unthinkable - upgrading NetBSD on a production machine.

Everythin went surprisingly well, even though it was an upgrade from  
1.6.2 to 5.0.2 on i386.

The only problem was the upgrade removed "unneccessary" libraries, and  
now libz.so.0 is gone.

No big deal, I thought, this was only used by gnome, so I went ahead  
and updated pkgsrc sources to HEAD.

Now I get errors like those at the bottom.

Is there any way to force pkgsrc's build system to actually delete the  
old files and install the new ones?
Or must I do a replace instead of an upgrade?  What does this do to  
dependencies I als want to be updated?

Cheers
        Oskar

=> Build dependency readline>=6.0: NOT found
=> Verifying update for ../../devel/readline
if /usr/pkg/sbin/pkg_info -K /var/db/pkg -qe "readline-[0-9]*"; then  / 
usr/pkg/sbin/pkg_info -K /var/db/pkg -qr "readline-[0-9]*" > /usr/ 
pkgsrc/devel/readline/work/.DLIST;  else  /usr/bin/touch /usr/pkgsrc/ 
devel/readline/work/.DLIST;  fi
pkg_info: Unrecognised PLIST command `@mtree +MTREE_DIRS'
===> Deinstalling for readline-6.1
Running /usr/pkg/sbin/pkg_delete -K /var/db/pkg -r readline-4.3
pkg_delete: Unrecognised PLIST command `@mtree +MTREE_DIRS'
pkg_delete: Unrecognised PLIST command `@mtree +MTREE_DIRS'
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
chardefs.h
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
history.h
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
keymaps.h
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
readline.h
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
rlconf.h
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
rlstdc.h
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
rltypedefs.h
original MD5 checksum failed, not deleting: /usr/pkg/include/readline/ 
tilde.h
Executing `/usr/bin/install-info --delete '/usr/pkg'/info/history.info  
'/usr/pkg'/info/dir'
Executing `/usr/bin/install-info --delete '/usr/pkg'/info/ 
readline.info '/usr/pkg'/info/dir'
Executing `/usr/bin/install-info --delete '/usr/pkg'/info/ 
rluserman.info '/usr/pkg'/info/dir'
install-info: warning: no entries found for `/usr/pkg/info/ 
rluserman.info'; nothing deleted
original MD5 checksum failed, not deleting: /usr/pkg/info/history.info
original MD5 checksum failed, not deleting: /usr/pkg/info/readline.info
original MD5 checksum failed, not deleting: /usr/pkg/info/rluserman.info
original MD5 checksum failed, not deleting: /usr/pkg/lib/libhistory.a
original MD5 checksum failed, not deleting: /usr/pkg/lib/libhistory.la
original MD5 checksum failed, not deleting: /usr/pkg/lib/libreadline.a
original MD5 checksum failed, not deleting: /usr/pkg/lib/libreadline.la
original MD5 checksum failed, not deleting: /usr/pkg/man/man3/history.3
original MD5 checksum failed, not deleting: /usr/pkg/man/man3/readline.3
pkg_delete: couldn't entirely delete package `readline-4.3'
=> Bootstrap dependency digest>=20010302: found digest-20080510
===> Checking for vulnerabilities in readline-6.1
===> Installing for readline-6.1
ERROR: readline-4.2 is already installed - perhaps an older version?
ERROR: If so, you may use either of:
ERROR:     - "pkg_delete readline-4.2" and "/usr/bin/make reinstall"
ERROR:       to upgrade properly
ERROR:     - "/usr/bin/make update" to rebuild the package and all
ERROR:       of its dependencies
ERROR:     - "/usr/bin/make replace" to replace only the package without
ERROR:       re-linking dependencies, risking various problems.
*** Error code 1