If you receive the bellow error message during installation:
Normally, opening a blank Excel sheet from your systems "Local administrator" account will resolve this error. Please follow the steps below and let me know how things go.
Open a command prompt with administrator privileges - click the Start Button (bottom left of your screen) and in the search dialog box type in cmd, the top option from there should be Command Prompt. Right click this and select Run as Administrator.
In the command prompt window type the following command:
net user administrator /active:yes
If done correctly, you should see a "command completed successfully" message. If so, log out of your current account and you should see an administrator account available at the log-in screen. Log into this account, open Excel, and open a new blank workbook. Close Excel and retry the installation from your user account.
If this does not work, log back in to the local administrator account and run the installation from there. If the installation completes, log back into your own user account and follow the steps available here to activate the add-in for your user's Excel.
Note: To deactivate this other account follow the same steps but use /active:no instead of /active:yes. It is suggested that you deactivate the local administrator account for system security.