When you went back to three months, did you change the date on the control panel? The date controls the months that go into the query. This is managed by the table in columns D:F on the Sales SQL and cells I1 & I2.

I'm fairly certain the connection string is working. It's the command string that would produce that error. Let's try one more thing: after you get the error can you go to Data -> Connections and get the connection string and command string and post them. I probably isn't the command string, but you might as well throw it in while you are there.

Also copy and paste the translated SQL.