One would think that the ESRI support would be able to tell you...
Anyway, what "configure SQL server to accept remote access" usually means is this:
In the SQL Server program group find the SQL Server Configuration Manager. When you have started it, select the node "SQL Server Network Configuration". You may see something like this:

If you see TCP/IP as Disabled, as I have highlighted it, right-click TCP/IP and select Enable from the context menu.
When you have done this, you need to restart SQL Server for the change to take effect. Select the node SQL Server Services. You will see something like this:

Right-click the highlighted node and select Restart from the context menu. Note that the name in parenthesis may be different from MSSQLSERVER.
Whether this will resolve your actual problem, I don't know, because the diagnostics from the ESRI support may not be accurate. If this does not work out, please share any error message you get.