I know a lot of you will scream at me for this one, but you might be using windows at work with cygwin and AVG.
Well, it seems that the recent patch (for today) contains a virus definition which is triggered by various libraries Cygwin's encoding area, which are almost certainly (99% certain) that they are false-positives (especially in Perl and Pythons libraries area)
Has anyone else got that issue?
JT