diff --git a/repository/Grafoscopio-Utils/GrafoscopioUtils.class.st b/repository/Grafoscopio-Utils/GrafoscopioUtils.class.st
index 83c9d5d..b85f580 100644
--- a/repository/Grafoscopio-Utils/GrafoscopioUtils.class.st
+++ b/repository/Grafoscopio-Utils/GrafoscopioUtils.class.st
@@ -68,9 +68,9 @@ GrafoscopioUtils class >> sanitize: url [
 	operations that rely on sane and well formed urls don't throw error messages."
 	| sanitized modUrl |
 	modUrl := url.
-	[modUrl endsWith: ' ']
+	[modUrl asString endsWith: ' ']
 		whileTrue: [ modUrl := modUrl copyFrom: 1 to: (modUrl size - 1)  ].
-	(url beginsWith: 'http://') 
+	(url asString beginsWith: 'http://') 
 		ifFalse: [ sanitized := ('http://', modUrl) asUrl ]
 		ifTrue: [ sanitized := modUrl asUrl ].
 	^ sanitized