I have just had avast 4.8 home detect several files as trojans. They are all .exe files produced by PicturesToExe. It detected them all as Win32:Trojan-gen. This has been documented in AVG also. See http://www.stevesforums.com/forums/view_topic.php?id=70358&forum_id=2 . No solution as yet. Any ideas? If I restore the file and then scan it from the context menu it does not detect a virus. Wierd.
You could also check the offending/suspect file at: VirusTotal - Multi engine on-line virus scanner and report the findings here. You can’t do this with the file securely in the chest, you need to extract it to a temporary (not original) location first, see below.
Create a folder called Suspect in the C:\ drive, e.g. C:\Suspect. Now exclude that folder in the Standard Shield, Customize, Advanced, Add, type (or copy and paste) C:\Suspect* That will stop the standard shield scanning any file you put in that folder. You should now be able to export any file in the chest to this folder and upload it to VirusTotal without avast alerting.
If it is indeed a false positive, see http://forum.avast.com/index.php?topic=34950.msg293451#msg293451, how to report it to avast! and what to do to exclude them until the problem is corrected.