Wait a moment... If you are using the 'Standard Glass' material then why does your glass have a slightly rippled or cloudy look to it? This kind of looks like you have applied a texture in the bump channel for the standard glass material. However, the bump texture is mapped to the decanters in such a way that it appears as striations (sp?) on certain sides or surfaces of the decanters. If this is so then it is just possible that those striations could be causing the striations in the shadows as light does or doesn't pass through them uniformly. Just a thought. It could be totally and completely off base, but I thought I would through it out there. :) If the glass material doesn't have a texture mapped incorrectly then something else is certainly wrong with with the way the entire glass material/decanters is/are being rendered and it is carrying over to the shadows.