Export Document to single web page, PDF and Word documents don't work. The progress bar reaches the end and after that gets stuck forever. Meanwhile no files are produced on the file system.

I can confirm this behavior in Pencil 1.3/Firefox 7.0

Works fine on 1.3.4 on Windows 7 here, can retest ?

I get a pdf file now, but there are problems with the rendering (elements not appearing in the PDF). I will provide more details later.