I installed the latest version of Libre Office Portable (4.4.2) today and immediately AVG identified the following file as containing a virus:
\PortableApps\LibreOfficePortable\App\libreoffice\program\senddoc.exe
This file was dated 2014-02-27 at 16:22
AVG reported the threat as Win32/DH.F27202FC{bQ}
AVG's reference to this virus can be seen here
http://www.avgthreatlabs.com/virus-and-malware-information/info/win-dh-bq/
I cannot tell if this is a false positive but I've deleted the entire folder to be safe and rolled back to the previous version of Libre Office.