Error View Concept: javax.el.ELException

Using OpenMRS to get familiar with it, I encountered the following problem:
I created a role called "Medic" with some priviledges (see attachment). In terms of priviledge related to Concepts, I gave him the following priviledges: View Concept Classes, View Concept Proposals, View Concepts.
Then I created a user AAA and assigned to him the "Medic" role.
AAA logs in with the AAA's credentials, he acceses the Dictionary and searches for a concept. In the Concept view, e.g. http://localhost:8080/openmrs/dictionary/concept.htm?conceptId=68, the user sees some info Id, UUID,Locale, Fully Specified Name,Synonyms,Search Terms, Short Name AND then an error (see attach):
"An error has occurred!
The following error happened somewhere on this page:
javax.el.ELException: Problems calling function 'fn:length'

(The full error stack trace output is in the source of this page.) "

Still, in the source code of the page, the code ends up like this:
<tr class="localeSpecific">
<th title="The text shown in report headers and other places where space is limited">
Short Name
</th>

<td class="en"></td>

</tr>
<tr class="localeSpecific">
<th valign="top

<font color="red">
<h2>An error has occurred!</h2>
The following error happened somewhere on this page:<br/>
javax.el.ELException: Problems calling function 'fn:length'

<br/><br/>
(The full error stack trace output is in the source of this page.)
</font>

<!-- There is no stack trace here because you are not authenticated -->

Regards!