How does the SkypeDialer work?

You will need to insure that Skype is installed - the add-in uses Skype's installed .dlls

The tool adds a menu item "Call via Skype..." to the context menu when you click on a contact in Outlook.  It also adds a ribbon button to the contact object in Outlook as well.  You can click on one of the 'speed dial' buttons, i.e. a button in the Call Manager such as 'Home', and the add-in uses Skype to call the person's phone number.  If you're calling a regular number (not a Skype handle), Skype-out charges apply (a fee that Skype charges and paid to them). 

If you've imported your Outlook contacts into the Skype application, a Skype to Skype button will be enabled for anyone participating on Skype, and you can make a Skype to Skype call.

'Unable to connect to the Skype4COM library"

I have Skype installed and working.  That's the message I get using Outlook 2007.

Skype needs to grant access

Be sure that Outlook is allowed to access the Skype library.  You can check program access via the Skype client under Tools - Options -  Advanced - Advanced Settings - Manager other's program access to Skype.