I'm back again, I was hacking your plugin using my personal Synology server and everything went well (I even succeeded to modify your code to integrate the possibility to display fields based on users roles).
Now I wanted to put on line my website, but my host only have MySQL 5.1.61. It forces me also to use WordPress 3.3. The problem is now that I can't see the fields of the participants database, neither on the back-end nor front-end. The fields are well presents (as there is a line representing it) but the name/title of the field is not displayed.
I tried lot of things, including complete fresh install with your last version 1.3.3 but it ends exactly to the same problem.
Have you an idea of the reason which is causing this behaviour ?
Thanks for your help