Why does Informatica hang and say "Not Responding" when connecting to ODBC Data Source
There are technically two windows for ODBC Data Sources in Windows.  The 64 bit window pops up when navigating to Control Panel > Administrative Tools > ODBC.  That connection for NETEZZA_I2B2_ETL worked.

However, the 32 bit dialog also had this data source.  But the connection failed there.  So after I fixed the connection, Informatica worked, and it created the source table.  Informatica must use the 32 bit ODBC connections, not the 64 bit ODBC connections.  "SysWOW64" means 32 bit.  Microsoft decided to keep the old folder names in Windows (System32 for example) and make them 64 bit folders in Windows 7.

C:\Windows\SysWOW64\odbcad32.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\ODBC\ODBC.INI

See this:

https://superuser.com/questions/713258/how-to-remove-odbc-data-source-if-driver-is-removed