Changes to the Home Page components in Summer 2015 release.

We have a scenario where on our Case object, we need two buttons that are color coded and has to appear to certain profiles and not to certain profiles.
These buttons when clicked will be routed to a different site that is integrated with our salesforce instance.
To get this done, our developer has created a html area with java script that would execute on the case object/based on the profiles and show the buttons to some profile users and hide for some.
But, since the html area will not/may not be working properly in future, with the summer release that is about to come, we did a work around.
We have saved that custom code as static resource.
We have put that code (along with other supporting codes like soap), on the custom links on the home page components.

{!REQUIRESCRIPT("/resource/1424715209000/HideCustomButton")}
{!REQUIRESCRIPT("/resource/1426710361000/sforce")}
{!REQUIRESCRIPT("/soap/ajax/33.0/apex.js")}
{!REQUIRESCRIPT("/resource/1426899248000/CustomCode1")}

The code is performing like it should, but we see this error, ie.
Faultcode: INVALID SESSION ID ERROR whenever the code is being executed. Not sure why this is happening. We are thinking of deploying this to production in future as HTML component may not work properly from summer.

Please advise on what needs to be done. I can explain in detail again to a developer that might help us.