When using SPX as a transport protocol in v4, you can register your Notes server names in the NDS tree and resolve IPX address without having to use SAP. By default, the Notes client installs with both NDS (Netware v4) and Bindery (Netware v3) methods available. The Notes client will first try to resolve using an NDS lookup and then fall back to SAP (bindery) lookup. If your organization is not using NDS or has not registered your Notes servers as NDS objects, then you will receive an error message when Notes tries to look up the server name in NDS.
To correct the problem, select File>Tools>User Preferences from the menu. Click the Ports icon. Select the SPX protocol from the list and click the SPX Options button. On the advanced dialog, select the Advanced Configuration and then select Bindery Services. This will make the v4 SPX client use the same method as the Notes v3 client and should eliminate your problem.