Here is what I did. I  created a new Class Library in VB. I opened the project and deleted that class. Next I added a COM Class. I copied your form to this project. I added a windows form. I added some code to open either a message box, the Windows Form or the Telerik form.

I created a BATCH file to copy the components to the local C drive and register the components (you will need to modify the paths for your environment).

I created an Excel sheet, added 3 buttons and 3 Macros so you could test each scenario. Unfortunately I cannot get my Excel sheet to run. I get a Microsoft error about licensing. I hope you have better luck. I do not use Excel very often. I am not sure if the License error I receive is Microsoft error or a Telerik error.