[scribus] Trouble with PDF/X3, PDF/X1a: Operator null is not PDF 1.3 compliant

[Michael Below]

Hi Kunda,

Am Mo 04 Mai 2015 17:55:26 CEST
schrieb Kunda Loves Scribus <scribus.user at gmail.com>:

> > Any idea how to get a valid PDF/X? I am attaching the .sla file, the
> > image is a 44.7 MB TIF.
> 
> Please start a bug on bugs.scribus.net and attach the .sla to that bug
> report. If you'd like you can make the bug private for only the devs
> to see it. You can also share a link to the TIF through dropbox or
> owncloud or whatever.  Thanks in advance!

I'm happy to help, but it looks like my file is valid PDF/X3 after all.
I talked to Jean Ghali via IRC yesterday, he checked it in Acrobat.
Possibly my printer is using a different software (and I saw
preflight errors with PDF Studio 10, but I don't know much about that).

Should I send my file anyway?

Cheers
 Michael