This sounds like the ODBC DSN that you are using might be available to the user running the script from the console, but not to the user who runs IIS. (which is, by default, a user called IUSR_MACHINENAME.)

If the DSN *IS* a user DSN, try making it a System DSN instead and see if you have the same problem. You might also want to enable ODBC tracing from the ODBC-Admin control panel.