DOMLex error when changing theme appearance

We are having an issue when trying to edit our theme through the Omeka admin. After changing any value and selecting “Save Changes”, a list of errors appear that all state:

Notice: Undefined property: DOMText::$data in /var/www/application/libraries/htmlpurifier/HTMLPurifier/Lexer/DOMLex.php on line 136

It repeats this error a number of times on the Omeka admin Appearance page. It also clears the entire Appearance form. No changes to the theme are applied. We are using the default Thanks, Roy theme.

Does this error occur on all themes or only Thanks, Roy?

This error is occurring on all themes. Even simply deselecting options such as “Display Featured Item” will cause the error to display.

Also, if this is helpful, we are running our Omeka installation on an Ubuntu 16.04 instance.

What version of Omeka are you running? It might also be helpful to get a rundown of the theme versions as well (click on the system info in the lower right-hand corner of any admin page)

Browser Mozilla/5.0 (X11; Linux x86_64; rv:57.0) Gecko/20100101 Firefox/57.0
Role super

Omeka 2.5.1
PHP 7.0.22-0ubuntu0.16.04.1 (apache2handler)
OS Linux 4.10.0-38-generic x86_64
MySQL Server 5.7.20
MySQL Client mysqlnd 5.0.12-dev - 20150407 - $Id: b5c5906d452ec590732a93b051f3827e02749b83 $
Apache Apache/2.4.18 (Ubuntu)
PHP Extensions
Regular apache2handler, calendar, Core, ctype, date, dom, exif, fileinfo, filter, ftp, gettext, hash, iconv, json, libxml, mysqli, mysqlnd, openssl, pcre, PDO, pdo_mysql, Phar, posix, readline, Reflection, session, shmop, SimpleXML, sockets, SPL, standard, sysvmsg, sysvsem, sysvshm, tokenizer, wddx, xml, xmlreader, xmlwriter, xsl, Zend OPcache, zlib
Zend Zend OPcache

BulkMetadataEditor 2.4
CsvExport 1.0.1
CsvImport 2.0.4
DefaultSort 1.2
DublinCoreExtended 2.2
FacetByMetadata 1.0.3
HideElements 1.3
Html5Media 2.6
PdfEmbed 1.0
PdfText 1.3
SearchByMetadata 1.2.1
SimplePages 3.0.8
SimpleVocab 2.1
TransferFileText 0.0.1

berlin 2.4
default 2.4 (current)
seasons 2.4

Hi, I’m the other half of this discussion. This problem does not happen on my machine which is using an exact copy of the installation and the database for development purposes. I am running the site on Windows via XAMPP, and most things are the same. The difference in my system information is that I am running the same installation on PHP 5.6.31/MySql 5.5.5… which means it might be a PHP version or extension issue.

What seems to be happening here is that there’s some difference with specific versions of PHP (and possibly even specific versions of libxml) that cause a problem with the HTML Purifier library.

The thing is that DOMText is supposed to have the $data property the error is complaining about. This might really be a problem with the PHP installation on the server that the problem is happening on.

plz do.we have a help in this issue, sry for my weak english

We’ll need some more details to help here. The output of the “System information” screen is a good start. (It’s linked to in the bottom-right corner of every admin page).