BUG CODE : NIM046443 When adding ScaleBar to web page with Master Page, you’ll get your javascript being broken. Solution : Based on http://forums.esri.com/Thread.asp?c=158&f=2276&t=291858 and http://support.esri.com/en/bugs/nimbus/TklNMDQ2NDQz  , simply set RenderOnClient=”false” on your ScaleBar control. It works on mine, I hope it works on yours too. Good Luck!