You know, I looked right at this and didn't see it.

Code:
// Showcase vs Store
if (STORE_STATUS == '0') {
define('', '</a>');
} else {
define ('TEXT_GREETING_GUEST', 'please enjoy our online showcase.');
Your problem is the line in red. You've edited that incorrectly. The original reads:

Code:
// Showcase vs Store
if (STORE_STATUS == '0') {
  define('TEXT_GREETING_GUEST', 'Welcome <span class="greetUser">Guest!</span> Would you like to <a href="%s">log yourself in</a>?');
} else {
  define('TEXT_GREETING_GUEST', 'Welcome, please enjoy our online showcase.');
}
If you want to remove the "Welcome Guest" part, it should look like this (color added for clarity).
Code:
// Showcase vs Store
if (STORE_STATUS == '0') {
  define('TEXT_GREETING_GUEST', '');
} else {
define ('TEXT_GREETING_GUEST', 'please enjoy our online showcase.');