Problem to go to older revision that had externals

Hi,

I have a working copy that includes data from an other repository with
an svn:externals property. Then I decide to import that data into my
repository and to remove the external. The following update that
switches the data from external to local causes trouble in some working
copies (Removed external is already locked). I tried to reproduce this,
but run into another issue. To model the update in other working copies
I switched my working copy to the revision that had the externals (svn
up -r nnn). This fails with "W155009: Failed to run the WC DB work
queue" and "E205011: Failure occurred processing one or more externals
definitions". "svn st -u" says I need to run cleanup, but after the
cleanup I get the same message from the status command. If I update now
I get an assertion from 'subversion/libsvn_wc/update_editor.c' line 1550.

What is wrong, how can I recover from that state?

A script to reproduce this is attached. Tested with svn 1.8.11 on
GNU/Linux 2.6.18, x86_64. The "How to report a bug" guideline asks for
such things like compiler and configuration options and the version of
Berkeley DB. Is there a command to get those information? All I did to
compile svn was "./configure && make && make install".

Thanks,
Holger