Problem

When using Internet Explorer 11.0.40 or older (like 11.0.38), you cannot import any TM Rules within Admin GUI->Setup->TM Settings. Attempting to import a Rule will result in the following error message:

Import Failed: Rules package name is not valid. It must contain only 
letters, digits, underscore('_'), dot('.') and space(' '), but cannot 
consist entirely of dots and spaces.

Resolution

To overcome the issue, in Internet Explorer navigate to Internet Options -> Security -> Custom level... -> Include local directory path when uploading files to a server and set it to Disable.