I uploaded the 7.7.1 files and changed the permissions for all of the directories and files as stated, but when I try to use the upgrade.php file I receive the following error:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at webmaster@maritime-sda-online.com to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.