Some of the f/*.xsl files xsl:import others but don't reference them as "filename.xsl" but as "../f/filename.xsl". This makes it harder to integrate FXSL into other software. I'd suggest that you run a quick search/replace and replace "../f/" by "".
Here is the list of affected files:
func-binRetrieve.xsl: <xsl:import href="../f/func-apply.xsl"/>
func-binSearch.xsl: <xsl:import href="../f/func-apply.xsl"/>
func-concat2.xsl: <xsl:import href="../f/func-curry.xsl"/>
func-curry.xsl: <xsl:import href="../f/func-type.xsl"/>
func-getWords.xsl: <xsl:import href="../f/func-str-takeWhile.xsl"/>
func-json-document.xsl: <xsl:import href="../f/func-lrParse.xsl"/>
func-lrParse.xsl: <xsl:import href="../f/func-apply.xsl"/>
func-product.xsl: <xsl:import href="../f/func-Operators.xsl"/>
func-Spell.xsl: <xsl:import href="../f/func-binSearch.xsl"/>
func-type.xsl: <xsl:import href="../f/func-XpathConstructors.xsl"/>
Even though there is catalog support now, this would still make things easier.