The installation process requires that the desired computer for the eConnect installation must be on a domain.
The following steps can be used to ultimately have the eConnect Integration Service that is running on a workgroup computer and the SQL Server is running on another computer in a domain. The process requires the installer to join the eConnect computer to the domain, run the installation for eConnect on the desired computer, and then remove the computer from the domain so that it is back in a Workgroup.
1.Create a domain account called eConnectService that will be used during the installation for the eConnect service account.
2.Join the eConnect computer to the domain and run the eConnect installation. During the installation, you will have to use the domain account from step 1 for the eConnect service account.
3.After the installation completes, remove the eConnect computer from the domain, and then create a local user account called eConnectService with the same password used for the domain account in step 1.
4.Run the statements listed here at a command prompt to set the URL reservation for the local account from step 3:
NOTE: You will receive "The parameter is incorrect" for any syntactical error (leaving off the trailing slash, for example).
a. netsh http delete urlacl url=http://+:80/Microsoft/Dynamics/GP/eConnect/
b. netsh http add urlacl user=computer_name\econnectService url=http://+:80/Microsoft/Dynamics/GP/eConnect/
(Replace computer_name with the computer name of the eConnect computer)
5.On the SQL server, create a local user account called eConnectService with the same password used for the domain account (and the local user account on the workgroup machine). Ensure that this local user account (on the SQL server) has a SQL login and is added to the DYNGRP role in the DYNAMICS and company databases.
6.eConnect for Microsoft Dynamics GP 2010 should now be ready to use on the workgroup computer.
In your case,
a) eConnect is already installed.
b) you should complete 4 to give effect to change of server.
Reference
http://support.microsoft.com/kb/2534520
Cheers!
Sanjay