diff --git a/main/inc/global_error_message.inc.php b/main/inc/global_error_message.inc.php
index 864e5a9718..63691c9aae 100755
--- a/main/inc/global_error_message.inc.php
+++ b/main/inc/global_error_message.inc.php
@@ -115,7 +115,7 @@ if (is_int($global_error_code) && $global_error_code > 0) {
 			}
 			$click_to_install = substr($InstallationDescription, 0, $pos);
 			$read_installation_guide = substr($InstallationDescription, $pos + 2);
-			$InstallationDescription = '<form action="main/install/index.php" method="get"><button class="save" type="submit" value="&nbsp;&nbsp; '.$click_to_install.' &nbsp;&nbsp;" >'.$click_to_install.'</button></form><br />
+			$InstallationDescription = '<form action="'.$root_rel.'main/install/index.php" method="get"><button class="save" type="submit" value="&nbsp;&nbsp; '.$click_to_install.' &nbsp;&nbsp;" >'.$click_to_install.'</button></form><br />
 					<a href="'.$installation_guide_url.'" target="_blank">'.$read_installation_guide.'</a>';
 			$global_error_message['description'] = $InstallationDescription;
 			break;
diff --git a/main/inc/lib/main_api.lib.php b/main/inc/lib/main_api.lib.php
index cc558e244d..40a5dc84cd 100755
--- a/main/inc/lib/main_api.lib.php
+++ b/main/inc/lib/main_api.lib.php
@@ -402,12 +402,11 @@ function api_get_path($path_type, $path = null) {
 
 		//
 		// Support for the installation process.
-		// Developers might use the function api_fet_path() directly or indirectly (this is difficult to be traced), at the moment when
+		// Developers might use the function api_get_path() directly or indirectly (this is difficult to be traced), at the moment when
 		// configuration has not been created yet. This is why this function should be upgraded to return correct results in this case.
 		//
-		if (!file_exists($include_path_sys.'/conf/configuration.php')) {
-			$requested_page_rel = api_get_self();
-			if (($pos = strpos($requested_page_rel, 'main/install')) !== false) {
+		if (defined('SYSTEM_INSTALLATION') && SYSTEM_INSTALLATION) {
+			if (($pos = strpos(($requested_page_rel = api_get_self()), 'main/install')) !== false) {
 				$root_rel = substr($requested_page_rel, 0, $pos);
 				// See http://www.mediawiki.org/wiki/Manual:$wgServer
 				$server_protocol = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') ? 'https' : 'http';
diff --git a/main/install/index.php b/main/install/index.php
index 9a2ce1e2e9..20ab63499c 100755
--- a/main/install/index.php
+++ b/main/install/index.php
@@ -15,6 +15,20 @@
 ==============================================================================
 */
 
+/*
+==============================================================================
+		CONSTANTS
+==============================================================================
+*/
+
+define('SYSTEM_INSTALLATION', 1);
+define('MAX_COURSE_TRANSFER', 100);
+define('INSTALL_TYPE_UPDATE', 'update');
+define('FORM_FIELD_DISPLAY_LENGTH', 40);
+define('DATABASE_FORM_FIELD_DISPLAY_LENGTH', 25);
+define('MAX_FORM_FIELD_LENGTH', 80);
+define('DEFAULT_LANGUAGE', 'english'); // TODO: To be examined.
+
 /*
 ==============================================================================
 		PHP VERSION CHECK
@@ -96,15 +110,6 @@ api_set_internationalization_default_encoding($charset);
 // Page encoding initialization.
 header('Content-Type: text/html; charset='. api_get_system_encoding());
 
-// Some constants
-define('SYSTEM_INSTALLATION', 1);
-define('MAX_COURSE_TRANSFER', 100);
-define('INSTALL_TYPE_UPDATE', 'update');
-define('FORM_FIELD_DISPLAY_LENGTH', 40);
-define('DATABASE_FORM_FIELD_DISPLAY_LENGTH', 25);
-define('MAX_FORM_FIELD_LENGTH', 80);
-define('DEFAULT_LANGUAGE', 'english'); // TODO: To be examined.
-
 // Setting the error reporting levels.
 error_reporting(E_COMPILE_ERROR | E_ERROR | E_CORE_ERROR);