uploaded pdf-documents generates code instead of pages in firefox and chrome (however they work in safari)

this is a new problem after having upgraded to mountain lion.

when I attach a hyperlink to my pdf-document that I like to display on the web - the pdf-document will not show up in Firefox or Chrome - it generates a lot of code instead.

I have only uploaded the files to my computer (not released on the web yet) - as I can see all files are neatly displayed in the appropriate pagefolder.

One of the themes (modern) provided as a standard feature in iWeb has been used. In Chrome the menu does not show up either (although safari and firefox displays the menu correctly)