Just started using Panasonic Tought Book cf-53 which is 64 bit. The download for cpn went to 98% and no higher. Has this to do with the fact my new machine is 64 bit. CPN worked perfectly on past notebook running vista. My GPS is usb port model1: gm12 and Output usr length 3 meters.
I would say that not being able to download a file has more to do with your internet connection.
If you refer to anything else, like that the installation went all the way to 98% and then it got stuck, it would help at least to know your operating system... Anyway, 64bit should not be a problem.
Location: where my little boat is ;-) now Philippines
Boat: Catamaran Schionning Wilderness 1320, built myself
Re: 64 bit
nope, I use CPN now on AMD E-350 (64 Notebook-processor, Nano-PC using Windows 8) and before on Intel, Core 2 Duo Prozessor (T7400) on Windows XP Ultimate and later Windows 7 and experimenting Ubuntu 10-64.
64 rarely has some driver issues, but never seen a problem related to oCPN