The bug has been opened on https://bugs.launchpad.net/ubuntu/+source/shared-mime-info/+bug/114241

"Binary package hint: update-manager

When upgrading from Edgy to Feisty. I get these errors:

Preparing to replace shared-mime-info 0.18-0ubuntu1 (using .../shared-mime-info_0.20-0ubuntu4_i386.deb) ...
Document `shared-mime-info' is not installed, cannot remove.
Document `shared-mime-info' is not installed, cannot remove.
Unpacking replacement shared-mime-info ...
* Wrong namespace on document element
* in '/usr/share/mime/packages/freemind.xml'
* (should be http://www.freedesktop.org/standards/shared-mime-info)
Aborted (core dumped)
...
Btw, freemind is a custom install. The installation did not go through because the syntax of the xml file is wrong (I think). This is the original file:

<mime-info>

 <mime-type type="application/x-freemind">

  <comment xml:lang="en">FreeMind Mindmap</comment>

  <glob pattern="*.mm"/>

 </mime-type>

</mime-info>

I changed it to:

<?xml version="1.0" encoding="UTF-8"?>
<mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
        <mime-type type="application/x-freemind">
                <comment xml:lang="en">FreeMind Mindmap</comment>
                <glob pattern="*.mm"/>
        </mime-type>
</mime-info>
...
What I actually mean is: the install/upgrade of shared-mime-info package did not go through because the syntax of the xml file is wrong (I think)."

Debug backtrace of the crash:

Program received signal SIGABRT, Aborted.
0xffffe410 in __kernel_vsyscall ()
(gdb) bt
#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb7cbadf0 in raise () from /lib/tls/i686/cmov/libc.so.6
#2  0xb7cbc641 in abort () from /lib/tls/i686/cmov/libc.so.6
#3  0xb7e0a62a in IA__g_logv (log_domain=<value optimized out>, log_level=G_LOG_LEVEL_ERROR, 
    format=0x804eec0 "* Wrong namespace on document element\n*   in '%s'\n*   (should be %s)\n", 
    args1=0xbfa6e7fc "�\032\006\bH�\004\b !ݷ&") at /build/buildd/glib2.0-2.12.12/glib/gmessages.c:497
#4  0xb7e0a669 in IA__g_log (log_domain=0x0, log_level=G_LOG_LEVEL_ERROR, 
    format=0x804eec0 "* Wrong namespace on document element\n*   in '%s'\n*   (should be %s)\n")
    at /build/buildd/glib2.0-2.12.12/glib/gmessages.c:517
#5  0x0804caf5 in load_source_file (filename=0x8061ac8 "/usr/share/mime/packages/freemind.xml")
    at update-mime-database.c:515
#6  0x0804dc67 in main (argc=Cannot access memory at address 0x2863
) at update-mime-database.c:635
#7  0xb7ca6ebc in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#8  0x080498f1 in _start ()