Value cannot be null. Parameter name formTemplate

While removing an InfoPath form template, you get following error:
Value cannot be null
Parameter name: formTemplate



It happens when you are removing the template using the Central Admin site. After you have started the removal process, the form does not disappear immediately from the listed forms and if you try to remove it again, you will get this error because the form had already been removed. Just go back using the browser’s back button and you won’t see the form listed there anymore.