OK, I've finally achieved comms between my PC and the XE-A203, here's how. I should explain I've taken over a business which has ceased trading and found a whole pile of kit including this ECR there, with no software, no leads, and no manual. I was unwilling to pay someone £50 to program it (or £25 or more for a cheap printer cable and a bit of software obtainable on the web for free) So if you're as mean as I and in the same position read on....
Go to
http://registrierkassen-kassenrollen.de ... ungen.html and I'd advise clicking on 'translate' if you don't speak German.
Scroll down the page and click on "Programmiertool XE-A203/213 (Zip-Datei - 4,6 MB)" it's right near the bottom, ignore the manual .pdf's above it - although they are more accurate than the US/Canadian ones you'll see elsewhere on the net.
When you click on the link the programmiertool will download as a zip file. I created a folder and unzipped all the files into it, ran the set-up and then followed the instructions as before. Surprise surprise it still didn't work, first the USB driver install screen didn't come up after the program installation and then when I tried loading data into the ECR I got a communication error message as before (see my post above)
I was about to give up when I went into Windows device manager (Right-click 'My Computer', click 'Manage', and then click 'Device Manager') clicked on the A203/213 (It might be under 'USB' devices or 'other' devices, but it'll be in there somewhere) and then 'update driver' and shazam it all worked after. I think it's picking up the driver sitting in the (no surprise here) drivers folder you unzip with the program. I've successfully done this on two PC's so it wasn't just luck.
This is version 1.1 for the 203/213 which is actually slightly more basic and clunkier than 1.0 for the 203 but it does work. Use any old USB printer cable but plug it straight into the USB ports your PC rather than using a hub as there are power issues. Good luck!

BTW I downloaded my own logo onto the thing which was a struggle as you are not allowed a logo with more than 35% black in it - I had to keep thinning down the font - and found it will take an input from the PC in reg mode as well as pgm mode. To check the receipt printing I kept having to press the 'no sale' key to get one out - in program mode it prints the entire status which is about a foot and a half long - in reg mode you just get a standard receipt. Worth remembering...