Can't access Perch admin

Hi, I may have broken something. :-/

I successfully installed Perch and edited the 'Perch' folder to 'admin' so login would be [site name]/admin/. I also successfully accessed the admin and even changed the branding, etc.

Then I had some trouble setting up content areas, and in a misguided effort to troubleshoot I renamed the 'admin' folder 'perch.' (I thought something was wrong with my file paths somewhere.) This immediately made the admin inaccessible, so I renamed it back to 'admin.' When renaming I also edited the php include to match the correct file name(s).

Now when I try to access the login area, I get this error message:

Warning: include(/home/content/78/9907078/html/perch/core/index.php) [function.include]: failed to open stream: No such file or directory in /home/content/78/9907078/html/perch/index.php on line 3

Warning: include() [function.include]: Failed opening '/home/content/78/9907078/html/perch/core/index.php' for inclusion (include_path='.:/usr/local/php5_3/lib/php') in /home/content/78/9907078/html/perch/index.php on line 3

Since everything I changed is back in its original place I don't know what else to do. Luckily the site was just beginning its Perch transition so hardly any work was lost... Do I have to reinstall?