Problems with linking to an external document.

Hi,

I'm using Twine 2 and Harlowe

I need to direct my users to an external coldfusion file at the end of my story. The file is held in the same folder that holds the published story. This is the code I'm using

Complete Course
(click: "Complete")[(goto-url: "taskend1.cfm")]

It works fine in chrome and firefox but in Internet Explorer 11 I get and Invalid Calling object error.

If anyone could shed any light it owuld be much appreciated.

Jon