diff --git a/src/includes/class/class.LSsession.php b/src/includes/class/class.LSsession.php
index 278e3161..713387c1 100644
--- a/src/includes/class/class.LSsession.php
+++ b/src/includes/class/class.LSsession.php
@@ -151,33 +151,33 @@ class LSsession {
     $path = ($external?'':LS_ROOT_DIR."/").$file;
     $local_path = ($external?'':LS_ROOT_DIR."/").LS_LOCAL_DIR.$file;
     $path = (file_exists($local_path)?$local_path:$path);
-    if ($path[0] != '/') {
+    if (!isAbsolutePath($path)) {
       $found = stream_resolve_include_path($path);
       if ($found === false) {
-        if (!$warn)
-          return false;
-        $log_msg = "includeFile($file, external=$external) : file $path not found in include path.";
-        if (class_exists('LSlog'))
-          self :: log_warning($log_msg);
-        else
-          error_log($log_msg);
+        self :: log(
+          ($warn?'WARNING':'TRACE'),
+          "includeFile($file, external=$external) : file $path not found in include path."
+        );
         return false;
       }
       else {
+        self :: log_trace("includeFile($file, external=$external): file path found using include path => '$found'");
         $path = $found;
       }
     }
     else if (!file_exists($path)) {
-      if (!$warn)
-        return false;
-      $log_msg = "includeFile($file, external=$external) : file not found ($local_path / $path)";
-      if (class_exists('LSlog'))
-        self :: log_warning($log_msg);
-      else
-        error_log($log_msg);
+      self :: log(
+        ($warn?'WARNING':'TRACE'),
+        "includeFile($file, external=$external): file not found ($local_path / $path)"
+      );
       return false;
     }
-    return include_once($path);
+    if (!include_once($path)) {
+      // Always log as warning in this case
+      self :: log_warning("includeFile($file, external=$external): include_once($path) not returned TRUE");
+      return false;
+    }
+    return true;
   }
 
  /**
diff --git a/src/includes/functions.php b/src/includes/functions.php
index a5dfc4e0..a7d8e302 100644
--- a/src/includes/functions.php
+++ b/src/includes/functions.php
@@ -669,6 +669,31 @@ function LSdebugDefined() {
     return "unknown : ".(string)$callable;
   }
 
+/**
+ * Check if a path is absolute
+ *
+ * @param[in] $path string The path
+ *
+ * @retval boolean True if path is absolute, False otherwise
+ */
+function isAbsolutePath($path) {
+  return strStartWith($path, '/') || strStartWith($path, './') || strStartWith($path, '../');
+}
+
+/**
+ * Check if a string start with another specified string
+ *
+ * @param[in] $string string The string to search in
+ * @param[in] $start_string string The starting string to check
+ *
+ * @retval boolean True if string start by specified one, False otherwise
+ */
+function strStartWith($string, $start_string) {
+  if (strlen($start_string) > strlen($string))
+    return false;
+  return substr($string, 0, strlen($start_string)) === $start_string;
+}
+
 /**
  * Dump file content
  *