When a mosaic dataset containing a raster attribute table function is moved to a different machine and published as an image service, the attribute table may be lost from the service.
In 10.1 SP1, re-author the attribute table function (point to source vat again), and save. This will serialize the attribute table as record set. After this, even if original table path is not accessible, the mosaic dataset and the image service (restart) can still work because it uses the serialized attribute table.