Hi and welcome to the RH community.
I have come across this in one of our larger projects although we are not big users of printed documentation. This is normally a sign that there is something inside the project that makes RoboHelp choke when it is all in one chunk. The official advice in these cases is to split the project up into smaller ones and merge them together. In the case of our "large" project, we have slightly more topics than you but lots of baggage files, embedded files and Captivate videos.
The RoboColum(n) @robocolumn Colum McAndrew
Thanks for the input guys, much appreciated. However I wouldn't say our project is that big or complex. It does contain many pages but this shouldn't cause RH to choke should it? and topics only got about 3 depths deep. Is this really considered "complex"?
Also, it does not explain why a brand new empty (well has the one default page) project still fails to generate into a PDF!
I don't think I said anything about your project being large or complex. Also you haven't said whether you looked at what was in the topic to which I pointed you and looked for what is set out there.
Do you get the same message with new projects as the one that reports malformed topics?
Are you generating to your local drive?
See www.grainge.org for RoboHelp and Authoring tips