Came across this problem recently on a heavily branded SharePoint Server site that had a blank site title – admittedly fairly rare.
Within the search centre on the results page the rightmost icon above allows you to add a location to the Windows 7 explorer favourites. From then on you can start searches in SharePoint without leaving Explorer.
click on the Icon You should then see a screen like this.
If you get an error ensure RSS is switched on for the site collection.
However if you see something like this
Notice the file name is corrupt – add a title to the site and it works again as expected.