It sounds like you have the wrong version of ezremaster. There is a "ezremaster.tcz" extension which is what you want. When you start it up it says it is for use for ezremaster 5.0 and later. The older version, "ezremaster-legacy.tcz" is for older versions.
It seems as the search in Apps Browser isn't showing the correct one when you search for "ezremaster", but if you don't search and scroll down the list you will see ezremaster.tcz which is what you want.