http://www.SyncCell.com/downloads/TestLotusNotesConnection.exe
If you are unable to connect, perform the following steps and then retry the test. This will often resolve the problem if you have upgraded from a previous Lotus version.
1) Open a Windows command prompt by opening Windows->Start, and run “cmd”
2) In the command window, type 'cd "c:\program files\IBM\Lotus\Notes"' (or wherever your Lotus installation is)
3) Then type “regsvr32 nlsxbe.dll”