You could just try do un-install all the packages you have installed and put them up again one after the other.

When uninstalling, you can choose to leave them in the folder, so getting them up again will be an easy task.

PS: I suppose it must be a block that renders on the frontend, so what was the last editing you did, which block did you add? try to remove the whole block/package or go back one version as Enlil said.

are you able to get to the dashboard at yoursite.com/dashboard or login at yoursite.com/login ?

If you're able to get into the dashboard, what was the last thing you made changes to before it messed up? Navigate to the page you made the changes to in the site map for instance and test if previous versions of the page work. If they do, remove the newest ones that don't work properly.

I was able to get to the Dashboard until I edited the code in the file manager to delete the following in the root/Main/config/site.php file:

<?php define('DIRNAME_APP_UPDATED', 'concrete5.6.2.1');?>"

Since that edit, when I try to access the Dashboard I get this error message:

"Invalid "DIRNAME_APP_UPDATED" defined. Please remove it from /home2/liveunit/public_html/Main/config/site.php.

I have tried to put: <?php define('DIRNAME_APP_UPDATED', 'concrete5.6.2.1');?>" back into the code, but then I just get a blank screen when I try to Access the Dashbhoard.

Should be <?php define('DIRNAME_APP_UPDATED', 'concrete5.6.2.1_updater');?>

I am trying to downgrade. I imported my backup into my database from concrete5.6.1.2. I have deleted the /concrete5.6.2.1_updater folder and I directed my site.php file to /concrete5.6.1.2_updater. I'm not getting the error anymore, but I still have a blank screen went trying to access my Dashboard.