SAP B1 - Outlook Integration - could not retrieve company list

We have a fairly recent installation of SAP B1 on a Windows SBS 2008 R2 server. Clients running the Outlook Integration application from Windows 7 clients with Outlook 2010. Configured SQL Native Client on PCs. Running the Outlook Add-In Configuration and pointing to correct server throws error, "could not retrieve company list". Not sure where I should start looking. ODBC connection tests successfully. Have tried both Trusted Authentication and SA. No difference. Tried typing in name of database manually and error states it cannot locate that database. Turned off Windows firewall to rule out port blocking. Has anyone ever seen this? Thanks.