Hi, I just wanted to say that I own a MSR505C as well and I'm also having issues with the demo software, although my problem is that I'm unable to write to a specific card -- I simply get an error regardless of what I try to write to it.

As such I want to write my own software for it that will hopefully be able to write to this card and that will work in GNU/Linux; I haven't gotten around to do that yet though but reading will be my first step and I'd like to be able to do raw reading as well, so if I can get it working I'll let you know. :-)