At this point it looks like the shadow Min Bias is too high. It sould be between 0.8 and 0.3 for most things, and even as low as 0.15 when a shadowcasting item is very close to the object receiving the shadows. I can't tell for sure, but there might be something strange with the bump map - are you sure that it is not a BUM file?. BUM files (the ones that look like embossed images) should only be used in the Gradient Bump node. Could you post a small section of the bump file as an image here?