Wierd Connection Error in 2010

[NoCoolHandle]

Ok.. connecting (trying) to a SQL r2 instance on my system.
basic connection string

Data Source=.\r2;Initial Catalog=blobstuff;Integrated Security=True

From Reporting services.. no problem.
From VS 2008 No Problem.

In 2010 I get

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - No such host is known.)

All protocols are enabled. Remote connections are allowed.
We did get it to work specifying the port that the instance is using,but it doesn't seem right that i will work in everyting other than vs2010 ..

It seems like a network library type error, but i don't see why i can get to it via VS2008.

Any ideas at all would be appreciated!

Rob

PS this works

 var c = new SqlConnection("Data Source=10.2.3.58,52479;Initial Catalog=BlobStuff;Integrated Security=True");