diff --git a/src/sacy/fragment-cache.php b/src/sacy/fragment-cache.php
index b5897b5..dee52e6 100644
--- a/src/sacy/fragment-cache.php
+++ b/src/sacy/fragment-cache.php
@@ -31,8 +31,11 @@ function get($key){
 
     function set($key, $value){
         $p = $this->key2file($key);
-        if (!@mkdir(dirname($p), 0755, true)){
-            throw new Exception("Failed to create fragment cache dir: $p");
+        $dir = dirname($p);
+        if (!is_dir($dir)) {
+            if (!@mkdir($dir, 0755, true)){
+                throw new Exception("Failed to create fragment cache dir: $p");
+            }
         }
         return @file_put_contents($p, $value);
     }
diff --git a/src/sacy/sacy.php b/src/sacy/sacy.php
index 4eb3b64..17b9057 100644
--- a/src/sacy/sacy.php
+++ b/src/sacy/sacy.php
@@ -102,12 +102,11 @@ private function urlToFile($ref){
             if (isset($u['query'])) return false;
 
         $ref = $u['path'];
-        $path = array($_SERVER['DOCUMENT_ROOT']);
+        $path = array($this->_cfg->getDocumentRoot());
         if ($ref[0] != '/')
             $path[] = $_SERVER['PHP_SELF'];
         $path[] = $ref;
         return realpath(implode(DIRECTORY_SEPARATOR, $path));
-
     }
 
 
@@ -223,6 +222,11 @@ public function __construct($params = null){
             $this->setParams($params);
     }
 
+    public function getDocumentRoot()
+    {
+        return realpath(str_replace($_SERVER['SCRIPT_NAME'], '', $_SERVER['SCRIPT_FILENAME']));
+    }
+
     public function getDebugMode(){
         if ($this->params['debug_toggle'] === false)
             return 0;
@@ -555,7 +559,7 @@ function writeHeader($fh, $work_units){
         fwrite($fh, "/*\nsacy javascript cache dump \n\n");
         fwrite($fh, "This dump has been created from the following files:\n");
         foreach($work_units as $file){
-            fprintf($fh, "    - %s\n", str_replace($_SERVER['DOCUMENT_ROOT'], '<root>', $file['file']));
+            fprintf($fh, "    - %s\n", str_replace($this->getConfig()->getDocumentRoot(), '<root>', $file['file']));
         }
         fwrite($fh, "*/\n\n");
     }
@@ -595,7 +599,7 @@ function getOutput($work_unit){
 
     function processFile($fh, $work_unit){
         if ($this->getConfig()->get('write_headers'))
-            fprintf($fh, "\n/* %s */\n", str_replace($_SERVER['DOCUMENT_ROOT'], '<root>', $work_unit['file']));
+            fprintf($fh, "\n/* %s */\n", str_replace($this->getConfig()->getDocumentRoot(), '<root>', $work_unit['file']));
         fwrite($fh, $this->getOutput($work_unit));
     }
 
@@ -631,7 +635,7 @@ function writeHeader($fh, $work_units){
         fwrite($fh, "/*\nsacy css cache dump \n\n");
         fwrite($fh, "This dump has been created from the following files:\n");
         foreach($work_units as $file){
-            fprintf($fh, "    - %s\n", str_replace($_SERVER['DOCUMENT_ROOT'], '<root>', $file['file']));
+            fprintf($fh, "    - %s\n", str_replace($this->getConfig()->getDocumentRoot(), '<root>', $file['file']));
         }
         fwrite($fh, "*/\n\n");
     }
@@ -648,7 +652,7 @@ function processFile($fh, $work_unit){
             $content = \Minify_CSS_UriRewriter::rewrite(
                 $content,
                 dirname($work_unit['file']),
-                $_SERVER['DOCUMENT_ROOT'],
+                $this->getConfig()->getDocumentRoot(),
                 array(),
                 true
             );
@@ -660,7 +664,7 @@ function processFile($fh, $work_unit){
             );
         }else{
             if ($this->getConfig()->get('write_headers'))
-               fprintf($fh, "\n/* %s */\n", str_replace($_SERVER['DOCUMENT_ROOT'], '<root>', $work_unit['file']));
+               fprintf($fh, "\n/* %s */\n", str_replace($this->getConfig()->getDocumentRoot(), '<root>', $work_unit['file']));
 
             fwrite($fh, $this->getOutput($work_unit));
         }
@@ -728,12 +732,13 @@ function getOutput($work_unit){
             return \Minify_CSS_UriRewriter::rewrite(
                 $css,
                 dirname($source_file),
-                $_SERVER['DOCUMENT_ROOT'],
+                $this->getConfig()->getDocumentRoot(),
                 array()
             );
         }else{
             return \Minify_CSS::minify($css, array(
-                'currentDir' => dirname($source_file)
+                'currentDir' => dirname($source_file),
+                'docRoot' => $this->getConfig()->getDocumentRoot()
             ));
         }
     }