GPS Data Logger Software - BT747

sorry for my english.

i just buy a gps logger 747a+. yesterday i  am doing a test. i put the button to NAV position and make a few kilometers with my car. when i came home i download bt747 software and i connect gps with pc. i installed the usb driver from cd that came with gps. the selected comport was 16.

when i start bt747 i saw the info of my gps and i also see 430 points. when i push the button download i receive in my pc a new file with the name doma.binand thats all! no file with the name GPSDATAxxxx.

when i was on the road i also push the button for trackpoint a several times but on bt747 there is now trackpoint/waypoints.

could someone tell me what i am doing wrong?