For your error code: "error 0070: segger module initialization failed" I had the same problem (only to upload from the remote but the download was OK ) and i think the remote always give the same error code for different problems.
Like yours, my remote gave the message: invalid CF version or corrupt flash.
I tried lots of things (the reset button and so on... ) but the solution for me was to open Neo Edit and to download an empty file (just open a new project and click on download)
For the USB-Serial adapter, it seems it doesn't work very well because there are lots of parameter that sometime you can't change (handshaking... ) some of them can only send informations but for some applications, you need TX + RX to receive the acknoledgement informations. In half or full duplex...
And sometimes, when you plug the USB card, the new com port is number 6 or 7 or 8 but the program you use only works with port COM 1 and maybe 3.
After, as tkrug says, there are different contolers in the usb adapters and the compatibility with the computer/motherboard is not sure at 100 %.
So try to find someone who has the same computer as you to know what he is doing.
An other possibility is to use a friend's computer (older) with a native com port (sometime it is more simple!)
