I'm using a SharePoint 2010 list as a DataSource in SQL Reporting Services 2008 R2 (see msdn.microsoft.com for more info on how to set that up).  When I use the query designer to get the acutal data I was getting the error message below.  I could see the columns in the chooser, so I knew I had permissions to at least see the list.
Exception of type 'Microsoft.SharePoint.SoapServer.SoapServerException' was thrown.  List does not exist.  The page you selected contains a list that does not exist.  It may have been deleted by another user.  0x82000006
Switching over the the "Edit as Text" I noticed the "Command type" didn't have anything selected.  I selected "Text", clicked the execute query button again and now I have data.
By the way, removing everything between and including the <ViewFields> tags will return all columns in the list... which may or may not be desirable.  I have them removed in the image above, but by default they're there.

