Rails - Mar 2006 - Connecting to SQL server on Mac OS X

I''ve had this problem before on FreeBSD - I fixed it (or worked  
around it) somehow but I can''t remember how.  Also it''s off
the
Google radar but I can''t believe I''m the only person to
experience it

I''ve installed FreeTDS and unixODBC from DarwinPorts, along with rb- 
odbc and rb-dbi.  I can connect to my SQL Server from tsql, but  
ActiveRecord won''t connect, and from in irb I get this error:

irb(main):003:0> dbh =
DBI.connect(''dbi:ODBC:MYDSN'',''MYUSER'',''MYPASS'')
NoMethodError: undefined method `default_attributes'' for  
#<ODBC::Driver:0x485a24 @attrs={}, @name=nil>
         from /opt/local/lib/ruby/vendor_ruby/1.8/dbi/dbi.rb:580:in  
`connect''
         from /opt/local/lib/ruby/vendor_ruby/1.8/dbi/dbi.rb:384:in  
`connect''
         from (irb):3

Can anyone help?  After 3 hours now I''m going crazy trying to  
remember what I''m not doing :-S

thanks
Ashley