If Citrix requires an authentication session for their downloads, you will have to precache the download manually (similar to the Java fixlets).
The simplest way to do this is by using the Software Deployment dashboard to generate the fixlet. The wizard will upload the file from your console computer, store it beneath wwwrootbes/Uploads, and create a fixlet with a download command to retrieve it from there.
It looks like you were trying to use the wizard but received the error from wizards.js (which is extremely hard to troubleshoot). Clearing your console cache as Zevanty suggests is a great first step. The only other thing that jumps out at me is that your file url was for I:\ which looks like a mapped drive letter. I’d recommend copying the software package to your console locally and trying to build the package from there.