diff --git a/lib/OpenLayers/Layer/Bing.js b/lib/OpenLayers/Layer/Bing.js
index 9a477f6c0b..51c2b9d045 100644
--- a/lib/OpenLayers/Layer/Bing.js
+++ b/lib/OpenLayers/Layer/Bing.js
@@ -224,7 +224,8 @@ OpenLayers.Layer.Bing = OpenLayers.Class(OpenLayers.Layer.XYZ, {
             new OpenLayers.Projection("EPSG:4326")
         );
         var providers = res.imageryProviders,
-            zoom = this.serverResolutions.indexOf(this.getServerResolution()),
+            zoom = OpenLayers.Util.indexOf(this.serverResolutions,
+                                           this.getServerResolution()),
             copyrights = "", provider, i, ii, j, jj, bbox, coverage;
         for (i=0,ii=providers.length; i<ii; ++i) {
             provider = providers[i];