I have imported subject tree and converted in XML as usual (I have done it many times before in 3.3.12)

/usr/share/eprints3/bin/import_subjects <archive id>
/usr/share/eprints3/bin/export <archive id> subject XML > /usr/share/eprints3/archives/<archive id>/cfg/subjects.xml

but the result is an empty xml. I tried to reindex  

./bin/epadmin reindex <archive id> subject and the result is:

You are about to reindex "subject" in the <archive id> repository.
This can take some time.

Number of records in set: 1
Continue [y/n] ? es
'el' is not a supported Xapian stem language, using English instead
Use of uninitialized value in concatenation (.) or string at (eval 97) line 54, <DATA> line 960.

I have attached the created xml file. What could be the problem?

Kostas Pgasinos

<?xml version='1.0' encoding='utf-8'?>
<subjects xmlns='http://eprints.org/ep2/data/2.0'>
  <subject>
    <rev_number>2</rev_number>
    <name>
      <item>
        <lang>el</lang>
      </item>
    </name>
    <depositable>FALSE</depositable>
  </subject>
</subjects>