In order to fix the issue, I recommend that you remove the program from your computer (Control Panel > Uninstall a program) and download and install it again. Also, make sure that the speaker on your phone is enabled and check if the error persists. If it is still not working, and the Speaker phone () option is disabled, it means that your phone is not recognized by the software or by the computer. To fix it, press Windows + R key combination, type devmgmt.msc and click OK. Expand the Universal Serial Bus controllers list, right-click on the driver and press Uninstall. Reboot the PC, connect the phone using the USB cable, press Scan for hardware changes icon from Device Manager and wait for Windows to retrieve the drivers. Also, I recommend updating the program using the Live Update button from the Setup menu:
If none of this helps, try contacting the developers.