Error Message in Joomla 2.5

Hi,

Not sure what I've done wrong - sorry if it is a silly question. I am working in Joomla 2.5 and added some packages - tried the flashcards first and created my own but when published it says this error message:

No values given [even though I input question and answer fields]

Warning: Invalid argument supplied for foreach() in /home/mydomain/public_html/libraries/h5pcore/core/h5p.classes.php on line 1474
Warning: First parameter must either be an object or the name of an existing class in /home/mydomain/public_html/libraries/h5pcore/core/h5p.classes.php on line 1506

For dialogue cards the error message read: : Invalid argument supplied for foreach() in on line : First parameter must either be an object or the name of an existing class in on line :

Is this a conflict with something I have on my Joomla? I have all plugins activated but noticed there were only 3 whereas your installation guide has a picture with 6. Any ideas?

Thank you!