I don't know what that other thread you refer to says, but here is about serial bit (and before others jump in, read the whole FAQ, of course ):

Connect your player to your computer via supplied serial cable. Fire up your favourite terminal emulator (Windows comes with Hyperterminal). Configure it for 115200 bps, 8 data bits, 1 stop, no parity, no handshake (neither hardware nor Xon/Xoff). Reboot the player by cycling the power. Observe (better yet, capture) serial output on your terminal emulator.

If the symptoms persist, describe them in detail and attach the captured serial output.

Good luck!