A Lulu developer was able to find out that the original error was coming out of the PDFLib library:
{"error_type":"PDFlibException","error_value":"Handle parameter or option of type 'page' has bad value 0"}

Does that mean anything to anyone?

On Mar 17, 2011, at 4:01 AM, Mojca Miklavec wrote:

> On Thu, Mar 17, 2011 at 08:52, Taco Hoekwater wrote:
>> 
>> As it says: "Directory not empty", perhaps you could look in the finder
>> or terminal to see what is still in there. I actually expect that
>> there is a Finder-specific file or folder there, which would mean that
>> the actual problem has nothing to do with the pdf itself, but just with
>> a difference between MacOSX and Ubuntu.
> 
> If that is true there is probably at least a file .DS_Store present on
> Mac OS X (which Finder won't show).
> 
> Mojca
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