I was having the same problems, then it turned out to be a simple permissions problem. Are the permissions on your Theme and Template Directory set to 777? Once I fixed that everything else worked.

Do you mean the templates_c and the themes directory at the root folder? The themes directory is already 777 except for the templates_c. I'm setting it right now. I'll try to reinstall AMS again now.

Stil doesn't work.
Still having error messages just like before. Plenty of them. The first line is:
Warning [PHP]: array_keys(): The first argument should be an array in file class/xoopsform/grouppermform.php line 135

It seems my problem is with the class/xoopsform/grouppermform.php file since all of the error messages point to this file.

Try this;

1) Backup database

2) Uninstall AMS in XOOPS control panel

3) Install AMS in XOOPS control panel

4) Goto Topic Manager in AMS and create a new topic (do not migrate data from news at this stage)

5) Goto Submit/Approve Permissions and set approve permissions and click submit.

6) Goto Submit/Approve Permissions and set Submit permissions and click submit.

7) Goto Submit/Approve Permissions and set View permissions and click submit.

8) Submit article from AMS link in the Main Menu block.

When you migrate data from any of the News modules, you MUST set the permissions on the topics before submitting any articles, as the migration script included in AMS 2.2 does not transfer any permissions. So even though you might have XYZ topics visable, if you don't set the permissions first you will corrupt your AMS tables as soon as you try submitting an article.

Thanks a lot Brash , I think it's working now. I'll get back to this topic if ever I'll have problems in the future.

A Million thanks to you and to the rest who tried to help me.

Mabuhay!!!