Hi Caroline,
I can't offer much help but I can tell you that's not the way our EndNote/Encore works. This is what happens with our Encore (http://search.wellcomelibrary.org):
Click on the “ icon in Encore > a file downloads immediately ("SearchResultsPage,searchResultsComponent.resultComponent.searchBrowseResultBibComponent.recordActionsComponent.endNoteExportComponent.linkComponent" - a RIS formatted file) > double click the file to open it which opens EndNote and asks me to choose a reference library...
I haven't gone any further than this but you can see that clicking the EndNote button in Encore gives a different result from what you're seeing. In fact, when I go to your Encore I get the same results from our Encore (I get no message about zotero nor a message to open a RIS file.
I don't have zotero installed or any zotero plug in so that may be why.
Our EndNote filter is at http://wellcomelibrary.org/using-the-library/how-to/EndNote-filter/ (adapted from Senate House Library's - I'm no expert!) if you want to take a look.
Thanks,
Natalie
Wellcome Library
