JQuery Rounded Corners on MasterPage

Hey folks,

I'm trying to use JQuery rounded corners to be applied to a div I have. However I can't seem to get the corners rounded. I'm actually applying on the master page so that its inherited on all of the sub-pages as well. I'm not sure if naturally JQuery exists within the project and so me referencing it twice could be an issue, can it be? 

I created as separate page to apply the JQuery and it works, however when applied to the MasterPage it doesn't call the function at all. Can someone advise if there is a particular way for using JQuery in the MasterPages please.

I'm using these references. Looking forward to a response! :)