When I go to "Choose from previously created fields", the fields are there and I can add them to the field group. However, when I save the field group they disappear again.
Solution:
It should be a server problem, please try to increase your server limitation, and test again, for example:
To hook into the add-to-cart workflow, it will need custom code to push some fields in the add-to-cart form. IMHO, I can use one or more Toolset Views and integrate them using custom code into the add-to-cart workflow.
Then, I can use Views to display orders and the orders items fields.
Problem:
Fatal error: Call to undefined function mb_strtolower()
Solution:
The multibyte string extension (mbstring) is required for Toolset.
You need to enable mbstring on your server. Please contact your hosting authorities and ask them to enable this extension. To solve this issue you need to install this extension on your server:
=> http://www.php.net/manual/en/mbstring.installation.php
