Issues connecting from MAC and unixOdbc

>I installed freetds successfully (I guess) using the option +mssql, and
>in fact I can connect from tsql to the server, but it fails when using
>isql, from unixodbc. The driver is configure correctly in odbcinst.ini.
>The entire command to install freetds is "port install freetds +mssql"
What am I doing wrong?
Federico

cat /tmp/sql.log
[ODBC][89993][1291662877.550017][__handles.c][459]
  Exit:[SQL_SUCCESS]
   Environment = 0x100804800
[ODBC][89993][1291662877.550362][SQLAllocHandle.c][375]
  Entry:
   Handle Type = 2
   Input Handle = 0x100804800
[ODBC][89993][1291662877.550917][SQLAllocHandle.c][493]
  Exit:[SQL_SUCCESS]
   Output Handle = 0x10080a200
[ODBC][89993][1291662877.551447][SQLConnect.c][3654]
  Entry:
   Connection = 0x10080a200
   Server Name = [mssql][length = 5 (SQL_NTS)]
   User Name = [minixel][length = 7 (SQL_NTS)]
   Authentication = [******][length = 6 (SQL_NTS)]
  UNICODE Using encoding ASCII 'char' and UNICODE 'UCS-2-INTERNAL'

  DIAG [S1000] [FreeTDS][SQL Server]Unable to connect to data source

[ODBC][89993][1291662877.557262][SQLConnect.c][4021]
  Exit:[SQL_ERROR]
[ODBC][89993][1291662877.557705][SQLFreeHandle.c][286]
  Entry:
   Handle Type = 2
   Input Handle = 0x10080a200
[ODBC][89993][1291662877.557771][SQLFreeHandle.c][337]
  Exit:[SQL_SUCCESS]
[ODBC][89993][1291662877.557868][SQLFreeHandle.c][219]
  Entry:
   Handle Type = 1
   Input Handle = 0x100804800