Cannot make a cache safe URL for "/_layouts/1033/XXXXXXXX/JS/wssSearch.js", file not found. Please verify that the file exists under the layouts directory.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: Microsoft.SharePoint.SPException: Cannot make a cache safe URL for "/_layouts/1033/XXXXXXX/JS/wssSearch.js", file not found. Please verify that the file exists under the layouts directory.

This error simply means that there is a bad reference in your master page/web part to a file that does not map to the layouts folder. In my case, I had the following line.

 <SharePoint:ScriptLink language="javascript" name="/_layouts/1033/XXXXXX/JS/wssSearch.js" Defer="true" runat="server"/>

I just changed it to 

 <SharePoint:ScriptLink language="javascript" name="/XXXXXX/JS/wssSearch.js" Defer="true" runat="server"/>

And Voila! It starts to work.