Xalan generates invalid output

Xalan-C++ generates invalid XML
output. Xalan-J works ok so it seems this is a bug in Xalan-C++.
The XML file generated with the transformation is not valid:

Before:

<map xmlns:ditaarch="http://dita.oasis-open.org/architecture/2005/"
title="MakeDoc's example demo/BE"
ditaarch:DITAArchVersion="1.1"
domains="(map mapgroup-d) (topic indexing-d)"
class="- map/map "
xtrf="c:\Pike\dita_problem\trialBE\dita\trialProjects.ditamap"
xtrc="map:1">

After the transformation:

<map title="MakeDoc's example demo/BE"
ditaarch:DITAArchVersion="1.1"
domains="(map mapgroup-d) (topic indexing-d)"
class="- map/map "
xtrf="c:\Pike\dita_problem\trialBE\dita\trialProjects.ditamap"
xtrc="map:1"

The xmlns definition is omitted and this is the problem because it is
used (ditaarch:DITAArchVersion). The error is:

Fatal Error.Occurred at file trialProjects_MERGED.xml, line 1, column
250. The prefix 'ditaarch' has not been mapped to any URI
SAXParseException: The prefix 'ditaarch' has not been mapped to any
URI (trialProjects_MERGED.xml, line 1, column 250)

I have uploaded the ZIP file with a small test. After unpacking look at those files:

run_xalanc.bat: generates trialProjects_MERGED_C.xml that is not
VALID. The batch requires to have xalan/xalan.exe in the PATH, you can
edit it and provide full path for the binary.

run_xalanj.bat: the same but in Java, generates VALID
trialProjects_MERGED_J.xml. Edit the batch before executing and change the
PATH for xalan.jar. The generated file seems to be valid, there is no
namespace bug there.

I am including trialProjects_pdf.log from Dita-OT toolkit also with the error
message above. Please contact me if you need further help, thank you.