Jorge did you try other QR readers, from what I've read some can read QR codes better then others. Remember I don't own a smart-phone so I'm just throwing suggestions to those (many) who do to try. You guys are my testers, plus you guys are smarter then the people I know with smart phones :)
I'm using a QR service to create the code, that I can't do by hand :-) There is a way to create a customized QR code and there are some guideliness to customizing. I followed the guidelines on what area of the QR code not to modify, it isn't working, maybe I modified to much of the QR code. Let me give you this example, which I didn't create but it should lead you Ice Tea.