Excel Files Are Not Opening?

I love the new taskbar and the "right click" on a pinned programme to access recent files & pinned files. However, while this feature works perfectly for Word, when I try to open an excel file from the taskbar, or even as an attachment to a received e-mail, I get the message " there was a problem sending the command to the program". The excel program itself opens if it is not already open, but the selected file doesn't. I can only open the file by going through "office button/open". If it is an e-mail attachment, I can only open it by saving it to one of my folders, and opening it via "office button/open". Additionally, once I attempt to open an excel file from the taskbar, the excel symbol on the taskbar displays a yellow/brown border instead of the normal border.