cbAddConn

There's 2 JS bugs related to IE. Both are fixed in CB 2.0 already. The one Nick linked above and the one below. Once both quickfixes are correctly applied you should be fine.

Issue 1: forge.joomlapolis.com/issues/4083
Quickfix: www.joomlapolis.com/forum/145-community-builder/220910-popup-windows-not-working-on-explorer-10?start=6#229629

Issue 2: forge.joomlapolis.com/issues/3887
Quickfix: www.joomlapolis.com/forum/240-potential-bugs/219270-drop-downs-on-ie-8-not-working?start=6#219512

I made both of those changes and it didn't resolve the error.

Then you likely have some other fatal JS error causing a conflict. Press F12 then view the Console when navigating to a profile and see if any fatal (red) JS errors are present.

Kyle, I did as you suggested and no errors are shown using F12/Console anywhere on the website including the profile page where I an trying to request the invite. Since this error is related IE, when I view the site using Firefox the error doesn't occur and allows me to complete the invite process.

You need to test with IE. IE9 and up includes a developer console accessible with F12 > Console. Aside from the two quickfixes there's nothing more I can suggest as both are confirmed working quickfixes. Please ensure the quickfixes were applied properly. Note there is a minified and non-minified version of JS files. The non-minified is used when debug mode is enabled so if you fixed the minified it won't resolve your issue if debug mode is enabled.