This is an oldish issue, but I did not find any resolution on it and had to get around it myself, so here goes.
It looks like it is a false positive by AhnLab virus scanner that Forefront uses. To get around it, save the files as PDF 1.5 instead. I've notified AhnLab of the issue and provided them test files. A simple lorem ipsum test document saved as PDF 1.4 in Scribus is tagged as "Win-Trojan/Exploit-PDF" by AhnLab (but not by 37 other scanners): http://virscan.org/report/e8854283def57f799ccaca9d699e5b6e.html Saving as PDF 1.5 (or even editing the first line of the pdf to read "%PDF-1.5") however makes the AhnLab heuristics happy: http://virscan.org/report/7bf8b6c5da9c321f9d9c0e5417982f45.html - Niilo
