No more products in backoffice after migration

[Dutch Green]

After a Migration from a subfolder to the root folder, there are no more products visible in the back office under catalog > products. The products are still visible and usable in the front office in website.

The error report looks like this. I know that one of these errors was already here before the migration so it does not seem to be related. I have searched forums but did not found any similar error after migration.

Warning: Function addCSS() is deprecated in /customers/9/3/5/sensationseeds.com/httpd.www/modules/posscroll/posscroll.php on line 37

in /customers/9/3/5/sensationseeds.com/httpd.www/classes/Tools.php on line 2611 Warning: Function addJS() is deprecated in /customers/9/3/5/sensationseeds.com/httpd.www/modules/posscroll/posscroll.php on line 38
in /customers/9/3/5/sensationseeds.com/httpd.www/classes/Tools.php on line 2611


The steps I have undertaken: 
- Cleared the cache manually
- Rebuild the htaccess file
- Re-build the entire index at preferences - search

 

Does anyone know what might be the solution?

Edited November 4, 2016 by Dutch Green (see edit history)