I had the same problem.

I solved it by creating a new view from exisitng fact table with a WHERE condition ISNULL(Country_Code,0) <> 0 and then creating a Distinct Count...

I had the same problem. I solved it by creating a view with a WHERE condition ISNULL(ID,0) <> 0 and then creating a Distinct Count out of this view

this is the same article that I referred to in the original post.

does your preview work?

Are you using Report Builder 1 or 2?

your URL seems to look like URL for Report Builder 1

whereas for Report Builder 2.0 it should be something like

https://server/ReportServer/ReportBuilder/ReportBuilder_2_0_0_0.application