Hi all
Upgraded a perfectly working 4.1.19 site to 4.5.5 and now getting "Error, unable to load libraries." trying to create new mod_hvp content:

With debugging set to maximum the error logs show,
[Tue Jul 29 22:54:07.283578 2025] [php:warn] [pid 3363252:tid 3363252] [client x.x.x.x:15950] PHP Warning: Cannot modify header information - headers already sent by (output started at /var/www/XXX/moodle/mod/hvp/editor/h5peditor.class.php:633) in /var/www/XXX/moodle/mod/hvp/library/h5p.classes.php on line 3296, referer: https://MYSITE/course/modedit.php?add=hvp&type&course=857§ion=0&return=0&beforemod=0
The scheduled task \core\task\h5p_get_content_types.task shows Start time Tuesday, 29 July 2025, 8:10 AM and Success
Execute scheduled task: H5P-Inhaltstypen von h5p.org herunterladen (core\task\h5p_get_content_types_task)
... started 08:10:01. Current memory use 33.3 MB.
0 new content types installed
... used 159 dbqueries
... used 0.36822891235352 seconds
Scheduled task complete: H5P-Inhaltstypen von h5p.org herunterladen (core\task\h5p_get_content_types_task)
Under MYSITE/h5p/libraries.php I see the same bunch of content types as the 4.1 and a huge bunch under Installed H5P libraries.
What is missing? Checked the moodledata/ permissions. The web server has write permission everywhere - and it is the same moodledata/ we had under 4.1, since the upgrade was "in situ".
What am I missing?
Moodle 4.5.5, mod_hvp 1.27.2 from 2024120900. The framework handler is "H5P framework v1.27 (h5plib_v127)". PHP (CGI) is 8.1.33.
(Edited by Mary Cooch - original submission Tuesday, 29 July 2025, 10:25 PM)