Dear list, I have the following sample: \setupinteraction [state=start] \startJSpreamble varia used now this.pageNum = 0 ; // start at 0 function GoToFirstSlide(label) { this.pageNum = 0 ; var rendition = this.media.getRendition(label) ; var player = app.media.openPlayer({ rendition: rendition, }); } function GoToLastSlide(label) { this.pageNum = this.numPages ; } function GoToNextSlide(label) { ++this.pageNum ; } function GoToPreviousSlide(label) { --this.pageNum ; } function SwitchFS() { if (app.fs.isFullScreen == true) app.fs.isFullScreen = false ; else app.fs.isFullScreen = true ; } \stopJSpreamble \setuppapersize[A9, landscape] \definefontfamily [mainface] [rm] [Latin Modern Sans] \definefontfamily [mainface] [ss] [Hans] \setupbodyfont [mainface, 25pt] \setupalign[middle] \setupfooter [style={\ss}] \def\SlideNavigationButtons{% \goto{A}[JS(GoToFirstSlide{mainsound})]% \goto{K}[JS(GoToPreviousSlide{mainsound})]% \goto{L}[JS(GoToNextSlide{mainsound})]% \goto{B}[JS(GoToLastSlide{mainsound})] \goto{{\ssb Q}}[JS(SwitchFS{})]% } \setupfootertexts[\SlideNavigationButtons] \starttext \definerenderingwindow[soundplace] [width=0pt, height=0pt] \useexternalrendering[mainsound][audio/mp3][sound.mp3][embed=yes] \placerenderingwindow[soundplace][mainsound] \dorecurse{25}{\null\page} \stoptext I don’t know why I get the following message: TypeError: a.doc is undefined It seems to be caused by "app.media.openPlayer", but the code is copied from the documentation Adobe released early this year. Does anyone know what is wrong here or what am I missing? Many thanks for your help in advance, Pablo -- http://www.ousia.tk