"Unable to locate client connectivity software ntwdblib.dll Check with your miscrosoft SQL Server database administrator to install the appropriate client software."
After googling around, I found the fix at http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=97161 (the last post). Here's how to fix the issue, just in case:
Find c:\windows\systems32\ntwdblib.DLL, possibly in your older 32bit Windows folder. Copy that to "c:\program files\CA\AllFusion ERwin Data Modeler" folder.
That's it. Try to connect again.
