Error connecting to remote server

Hello,

I have a problem trying to connect a remote sql server. The error:
An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

DEVSQL computer name
RealitySolutions instance name

Using a windows application on a LAN.

my connection string is:
connectionString="server=DEVSQL\REALITYSOLUTIONS; database=ServiceMaster; Integrated Security=True

This is what I have done:
Enabled TCP/IP and named pipes and share memory protocals on my instance in configuratoin management.
surface area configuration I have enabled enabled remote connection using TCP and Named pipes.

I still get the above error message.

Any help will be most grateful, and I think i have tried everything.

Thanks

Steve