rpm -Va --root /external_folder fails sometimes

Description of problem:
rpm -Va --root /external_folder fails sometimes

Version-Release number of selected component (if applicable):
rpm-4.4.2.3-15.el5

How reproducible:
sometimes

Steps to Reproduce:
$ yum --installroot=/root-postgresql install postgresql-server

$ rpm -V --root /root-postgresql postgresql-server
^^^ works well even in a long loop

$ rpm -Va --root /root-postgresql
^^ firstly it works

# secondly that cmd on same machine
$ rpm -Va
S.5....T c /etc/pam.d/system-auth
rpmdb: /root-postgresql/var/tmp: No such file or directory
rpmdb: unable to create temporary backing file
rpmdb: /root-postgresql/var/tmp: No such file or directory
... after +- 10 lines it ends

# thirdly
$ rpm -Va --root /root-postgresql
rpmdb: /root-postgresql/var/tmp: No such file or directory
rpmdb: unable to create temporary backing file
rpmdb: /root-postgresql/var/tmp: No such file or directory
rpmdb: unable to create temporary backing file
rpmdb: /root-postgresql/var/tmp: No such file or directory
rpmdb: unable to create temporary backing file
rpmdb: /root-postgresql/var/tmp: No such file or directory
rpmdb: unable to create temporary backing file

#thousands and thousands lines

rpmdb: unable to allocate space from the buffer cache
error: db4 error(12) from dbcursor->c_get: Cannot allocate memory

Actual results:
rpmdb: /root-postgresql/var/tmp: No such file or directory

Expected results:
no errors

Additional info:
found during testing
https://bugzilla.redhat.com/show_bug.cgi?id=434150

Path for temporary databases ends up being wrong when chrooted in the way verification does it. Easiest fix is to just disable the dependency caching on chrooted verify.

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2009-1371.html