Blank user-id and p/w are only supported under SQL89. You can still use SQL89 w/ Progress v9 using startup params.
The following is from the datadirect website (they write the merant odbc drivers for Progress)
www.datadirect.com
Analysis
Does the Progress ODBC 3.60 or DataDirect 4.10 SQL-92 Progress driver support a blank user id and password when connecting with an application?
Resolution
Progress does not support a blank user id and password when using the Progress 9.x SQL-92 engine with ODBC. This is a security feature of SQL92. A valid SQL user id and password must be created by the Progress DBA (sysprogress).
To workaround this feature Progress 9.x provides both the SQL-89 and SQL-92 engine. Using the Progress documentation and setup options, a Progress Broker (OIB) can be started, which allows a user to use the Progress 9.x SQL-89 engine. The user will then be able to pass a blank user id and password.
*NOTE* The ODBC Progress 3.60 and DataDirect 4.10 SQL-92 driver cannot connect to a SQL-89 engine, only the SQL-92 engine. The DataDirect ODBC 4.0 Progress 7/8 driver will connect to a SQL-89 engine, but not the SQL-92 engine.