After conversion error, API call for job "result" returns 500 server error

_From [john.bru...@gmail.com](https://code.google.com/u/108810182039435316737/) on October 04, 2013 23:53:36_

What steps will reproduce the problem?

1. Reproduce the error in issue https://github.com/daisy/pipeline/issues/368.
2. Check the job results. It is marked as DONE
3. Ask for the job results. Through the cli, this might be:

cli/dp2 results --file /some/place b5e57076-9c24-4d80-88b1-bdc3d30f28a0

What is the expected output? What do you see instead?

The server returns a 500 internal error. The job log looks something like this:

2013-10-04 13:30:08,744 [ERROR] com.xmlcalabash.library.XSLT - bundle://18.0:1/xml/xslt/html-chunker.xsl:22:err:XPTY0004:A sequence of more than one item is not allowed as the second argument of concat() (2, 3)
2013-10-04 13:30:08,748 [ERROR] com.xmlcalabash.library.XSLT - A sequence of more than one item is not allowed as the second argument of concat() (2, 3)
2013-10-04 13:30:08,751 [ERROR] com.xmlcalabash.library.XSLT - A sequence of more than one item is not allowed as the second argument of concat() (2, 3)
2013-10-04 13:30:08,754 [DEBUG] org.daisy.pipeline.push.Poster - Status changed 1b556daf-22d3-488c-8ec4-dae1861242f2->DONE
2013-10-04 13:30:09,605 [ERROR] o.d.p.w.xml.XmlValidator - element "results" incomplete; missing required element "result"(1, 637)
2013-10-04 13:30:09,606 [ERROR] o.d.p.w.xml.JobXmlWriter - INVALID XML:


<nicename>DTBook to EPUB3</nicename>
<description>Converts multiple dtbooks to epub3 format</description>

What version of the product are you using? On what operating system?

v1.6-beta on Ubuntu Linux Please provide any additional information below.

_Original issue: http://code.google.com/p/daisy-pipeline/issues/detail?id=369_