Adding to Ian's comments, the last enterprize wide system of Addin's that I put together actually required only a script added to each JMP users startup file, along with a .jmpcust(change to the pull down menus). The pull down menu basically popped up a Web Browser Window, which listed the Addins available. Using the Web Browser Window allowed for the addition to the list of addins without having to go out and touch each JMP user's system. When a user selected an addin, it installed the adding in a standard JMP fashion. However, each adding was written such that the first thing it did when run, was to download a new copy of itself, and write it to the addin's directory. Then run the addin script. This ensured that the user always had the most recent copy of the addin. The overhead of copying the addin proved to be unnoticable to the users. The reason the code was copied and not just run from the central site was that the addins checked to see if the required network connection was ther, and if not, the addin ran the version that was copied down the last time the addin was run. This system was very successful and continues to run after it's implementation back when JMP 9 was just released.
Jim