EQASCOM only supports com port numbers up to 16 for mount communications and GPS interfaces. Depending on the hardware and drivers you use you may therefore have to reassign com port numbers allocated. This is quite easy to do.
1. Open up the control panel and select system.
2. Select the hardware tab and click the device manager button.
3. From the device manager double click your com port and select the port settings tab.
4. Click the advanced button.
5. From here you can choose an alternate com port number. You can use numbers that are apparently already assigned so long as by the time you've finished every device has a unique com port number assigned.