In some odd situation, SharePoint Designer (SPD) 2010 would throw this error:

“soap:Server was unable to process request. Value does not fall within the expected range”

SPD does not open the site with name it was originally defined.  For example, the site was created as http://machine_name:3000/, but SPD connects it as http://localhost:3000/

SPD should connect the site with name/url defined at its creation.