First try to remove the "port" and "baud" line completely.

If doesn't work try to change the port number each from 1 to 9.

Next step try to change the baud to "4800" with all the ports.

If still no result, try to add this line to the [GPS] section:
protocol = "NMEA"

I know this is many options and not easy to manage, but there are no easy solution for this device as far as I know. Unfortunately I don't know any port scanning program what would run on this.