First, make sure your tx is connected to the rx line of the myrio and rx is connected to tx. Check the Vin voltage and gnd connection. I've never used a myrio and I would first check v communication to a serial port on the pc. I would also use a scope to look at the tx line of the gps unit to see if it is transmitting anything.
Quite frankly, that note from from NI does not address the most common problems with a timeout error. I don't think I've ever fixed it by increasing the wait.
