@DarkMan, when you see the message WARNING: An Error occurred, please refresh the page and try again., there is a myDEBUG-*.log file present in your /logs directory that contains the details of the error.

Note: If a file's name starts with myDEBUG-adm-, then that file identifies an admin-related issue and includes your secret admin folder name. If you post the contents of one of those files (using the #/CODE button in the menu-bar when you are writing your post), make sure to xxx-out that admin-folder-name!