I am trying to add file hightail.exe to the block/allow files list but Webroot will not add it.

Windows 7 Pro on a 64-bit Lenovo T450. I have an app, "Hightail Express," that may not be connecting with my account with Hightail on the web, so I thought I would add it to the allow files list in Webroot. I click on Add File, and navigate to "hightail.exe "in the C:Program Files (x86)HightailExpress" directory, double click on the file, but it is not added to the list. What am I missing here?
-- Arthur