This is caused by a Microsoft Office security update that was issued on 12/9/2014. These patches break any Excel customizations that have ActiveX controls, it’s not just the eOne templates, it is any Excel VBA customizations that include ActiveX controls.
There are 2 ways to resolve this:
1. Uninstall the patches in Windows Programs and Features. The patch for Office 2010 is KB 2553154 and the patch for Office 2013 is KB 2726958
2. Delete the MSForms.exd for Excel. This file will automatically get recreated when you launch Excel
a. To delete the MSForms.exd file, you need to browse to the c:\Users\[user.name]\AppData\Local\Temp\Excel8.0\ folder
b. Delete only the MSForms.exd file located in there.
c. This file is user specific, so you need to delete it from each individual users temp folder.