First thing to check: from the SQL Server, can you connect to the SQLExpress instance (with SSMS or SQLCMD)?
If not, there's no need to involve the linked server in your troubleshooting.
I would go ahead and create an alias for the sql express instance. I enabled the remote connection, TCP/IP and Named Pipe in the Express machine and I am able to view the server name of the machine in the Netwerk Servers list while trying to connect to the Database Engine from SSMS. However, I am unable to connect to the same.
What could be the problem? Can someone provide me the steps to connect to an express instance from a Developer Instance..