Today I've found that when BridgeServer works under IIS 6 (on Windows Server 2003), it cannot connect to remote database, even with all changes in machine.config file (as I did for IIS 5 on Windows 2000). I've spent some time to investigate this problem (thanks to Pawel Bojkowski for his persistency and assistance with tests) and I've found the following solution of this problem:

1. Open "Computer Management" tool ("Start/Control Panel/Administrative Tools/Computer Management").
2. Expand "Services and Applications" node.
3. Expand "Internet Information Service (IIS) Manager" node.
4. Right click "Application Pools". 
   • Select "New" menu item.
   • Then select "Application pool..." menu item.
   • Specify Application Pool ID as "BridgeServer".
   • Click "OK".
   • Right click on "BridgeServer" application pool and then select "Properties" menu item.
   • Select "Identity" tab.
   • Change "Application pool identity" to "Configurable".
   • Provide domain user name and password. This user should be member of IIS_WPG group and have enough access rights to the folder where VSS database is stored.
   • Click "OK".
5. Expand "Web Sites" node.
6. Expand "Default Web Site" node.
7. Right click "BridgeServer" web application and then select "Properties" menu item.
   • Change application pool to "BridgeServer".
   • Click "OK".
8. Restart "Default Web Site".