Looks like Trend Office reports PSPadShell.dll incorrectly as a threat, that's why some users think it's corrupt when the archive comes back.
http://about-threats.trendmicro.com/ArchiveMalware.aspx?language=us&name=PAK_Gen eric.005 -- <http://forum.pspad.com/read.php?6,57334,57343> PSPad freeware editor http://www.pspad.com
