With the driver that is currently on the webpage for Maestro 6-channel (version 130422) I am not able to get the Maestro to work under Windows 7 (64 bit Ultimate).
However, I had version 121203 from earlier available, and with that driver it works fine.
What happened was that it was not possible to open the serial port for the servo controller at all. However, the TTL serial port worked fine.
With the old driver both seem to work fine.
Posting this just in case this is an issue somebody should look in to 