Cant access site anymore

A couple of days ago, I put together a simple site (mytherapysession.com/waoa). Got everything the way I wanted it, and tested. Everything worked perfectly. So, I downloaded everything for that site, and then created a new one (mytherapysession.com/nbla). This site works perfectly as did the first one. Tested both sites on different devices and again, everything was perfect.

This morning I wake up and go to check out the sites again, just to make sure there wasnt anything that I may have missed. While the second site is still functioning perfectly, the first site would not allow me to login, or create any new accounts. COmpletely perplexing. So, I used my ftp and deleted all but the .htaccess files in both the cache, and cache_public folders. Now The issue is worse. At least before I could see the site, I was just getting username and/or password incorrect errors, now I am getting:

Warning! Cannot evaluate Menu Cache.
Warning! PageView cache cannot be evaluated. Please recompile.
Warning: Cannot modify header information - headers already sent by (output started at /home/mytherap/public_html/waoa/inc/classes/BxDolMenu.php:52) in /home/mytherap/public_html/waoa/inc/design.inc.php on line 115
1 Sorry, site is temporary unavailable. Please try again later.

I am totally confused, cause the second site still works, and it is a duplicate of the first one. Any help would be greatly appreciated.

The time I got that error I had forgot to make sure the permissions were proper on the caches.  Also, if you are running any caching, such as APC, or Memcache; you have to clear out the caches in them.

thanks GG - I do have APC, but have no clue how to clear those caches - looks like Google time.

I think there is a way to clear through some interface but just restart php and that will clear the caches.

i had tried that, and it did not work. Plus tried to view the APC statrs using the apc.php page, and I keep getting a database error for a dolphin file - beyond confused now.

Phew - got it working - it was crazy. For some reason, my backups were not being saved to my home2 directory, and were being saved in each cpanel folder, thus I ran out of drive space. On top of that, the mysql database was corrupted. Once I got those issues resolve, I lost all of my language keys, but fortunately recompiling them brought them back. I was going ape **it over here not knowing what was going on. Thanks again GG, because of your input, I will be sure to keep an eye on my APC cache (now that I got that page working as well).