Thanks for reporting this, Frank. Looks like there are two distinct but related problems here. First, the documentation should not show backslashes, because those are indeed illegal in URIs. That's an easy fix. Second, the variable substitution is resulting in an invalid URI (because of the backslashes). This is a trickier problem, because variable substitution has no idea what the semantics of a variable value are. It could be a file path, a person's name, a database connection, or someone's favorite color. We're either going to have to put some context around variable substitution so that it can intelligently replace backslashes with forward slashes, or we're going to have to deal with the problem further down the line before converting values to URIs. I'm going to have to think on this one for a bit.