Hi Mike,
i think I can help you here. As you are using UFRAW I think you must be using linux right? First of all, congrtulations on a great operating system!!!
I use LM distro and am very happy with it.
I also like you tried UFRAW as it is easy to install from the synaptic repo database and offers a variety of useful functions. I also had this strange border untill I realised that it was the distortion of the lens! You have to select and compensate for this under one of the setting, cant remember which one now but it is there.
My next piece of advice, stop using UFRAW. Get yourself either RAWTHERAPEE or if you are feeling very adventurous get darktable, which many claim is comparable to lightroom.
If you have any further questions please let me know.