I have had some troubles recently accessing Firebird from Sybase
PowerBuilder, and I just found out why from some helpful folks on a
PowerBuilder newgroup.

I am using the cheapest version of PowerBuilder, PB Desktop. It has
support for ODBC drivers, but it turns out that ODBC support is
limited, and does not include Firebird. I have been told you have to
upgrade to PB Professional or PB Enterprise to get support for
Firebird. (They are much more expensive!)

The exact error message you get when you try to connect to a Firebird
ODBC Data Source in PB Desktop is:

Invalid or Unsupported Data Source "DSN name"

Just thought this would be helpful to others on this list, in case
you
have the same problem.