You don't tell us what's in "Data/verysimple.xml" - that is where the problem is occuring. The file is obviously not XML.

But I also can't recommend strongly enough to NOT USE XML::XSLT. Sorry for shouting that, but it needs to be said. This is a very bad module that does not implement XSLT, but a very *very* small subset of it, and the parts that it does implement are often done wrongly. In short, steer clear, and go for XML::LibXSLT, XML::Sablotron, or XML::Xerces.