Sounds like SMF's Settings.php file is missing some stuff. suspensions/unsuspensions don't edit any files on your site (besides .htaccess), so I'm not sure how the unsuspension could have caused that. Try fixing your Settings.php file
1) Try editing those files in the cPanel file manager to see if they have contents or not
2) If they do not, re-upload SMF and manually create your Settings.php file with your existing database, username, and password -- that way you will not lose any of your posts.
You're on the old adfree plan, which used to have a 1GB cap on disk space, although cPanel seems to indicate otherwise now. I think there is something screwy with your account, so I'm going to ask an admin to look at it.
Edit: This post now useless, Skizzerz' is more accurate but I'm leaving mine here in case it should be on adfree-infinity, in which case this one is more accurate.
The issue might be in the process of fixing itself; that error can come up when the hdd for the server gets close to full. I found an account I'm cleaning out now who was on your server and in major violation of the file hosting policy, so give it about 10-20 minutes and see if it fixes itself