First of all, Will, thank you and all contributors for a great php library! I discovered it recently and the more I use it, the more I appreciate it!
Having said that, I also had some difficulties using the fXML class, especially traversing it using xpath. My particular problem was that I did not consider the declared XML namespace. This is entirely my fault, of course, but I think users will benefit from a slight extension of the fXML documentation. I suggest putting together a full example where the XML document has a namespace and the example reflects that.
Let me know if that sounds reasonable and if so, I'll find some time to write and post back here the addition I propose.
Let me know, thanks! Yassen