diff --git a/lesscpy/lessc/parser.py b/lesscpy/lessc/parser.py
index bbe136b..13b6952 100644
--- a/lesscpy/lessc/parser.py
+++ b/lesscpy/lessc/parser.py
@@ -491,6 +491,11 @@ class LessParser(object):
 #
 #    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 #  
+
+    def p_argument_list_empty(self, p):
+        """ argument_list       : empty
+        """
+        p[0] = ''
         
     def p_argument_list_aux(self, p):
         """ argument_list       : argument_list argument
diff --git a/lesscpy/test/css/ie.css b/lesscpy/test/css/ie.css
index 50046ee..04234c2 100644
--- a/lesscpy/test/css/ie.css
+++ b/lesscpy/test/css/ie.css
@@ -13,3 +13,14 @@ body {
  > body {
 	*zoom: 1px;
 }
+.ui-datepicker-cover {
+	display: none;
+	display: block;
+	position: absolute;
+	z-index: -1;
+	filter: mask();
+	top: -4px;
+	left: -4px;
+	width: 200px;
+	height: 200px;
+}
diff --git a/lesscpy/test/css/ie.min.css b/lesscpy/test/css/ie.min.css
index 66e71bb..8139751 100644
--- a/lesscpy/test/css/ie.min.css
+++ b/lesscpy/test/css/ie.min.css
@@ -3,3 +3,4 @@
 .nav2{filter:progid:DXImageTransform.Microsoft.gradient(startColorstr="#333333", endColorstr="#000000", GradientType=0);}
 body{*zoom:1px;}
 >body{*zoom:1px;}
+.ui-datepicker-cover{display:none;display:block;position:absolute;z-index:-1;filter:mask();top:-4px;left:-4px;width:200px;height:200px;}
diff --git a/lesscpy/test/less/ie.less b/lesscpy/test/less/ie.less
index 37ed8eb..ddbecac 100644
--- a/lesscpy/test/less/ie.less
+++ b/lesscpy/test/less/ie.less
@@ -20,4 +20,16 @@ body {
 }
 >body {
 	*zoom: 1px;
+}
+/* IE6 IFRAME FIX (taken from datepicker 1.5.3 */
+.ui-datepicker-cover {
+    display: none; /*sorry for IE5*/
+    display: block; /*sorry for IE5*/
+    position: absolute; /*must have*/
+    z-index: -1; /*must have*/
+    filter: mask(); /*must have*/
+    top: -4px; /*must have*/
+    left: -4px; /*must have*/
+    width: 200px; /*must have*/
+    height: 200px; /*must have*/
 }
\ No newline at end of file