A dial is just the visible manifestation of a channel. So the first question is do you want to get rid of the dial or the channel as well? In a Poser library file, each channel has a parameter named 'hidden' which has a value of "1" = hidden, or "0" = displayed. To hide the dial you can change this value either by editing the file in a text editor, or by applying a pose in Poser.

To delete the whole channel, if the file is stored in an uncompressed format you can delete the channels in a text editor, or a cr2 editor such as CR2Builder, or Cr2Editor. If the file is in a compressed format you will have to decompress it first.

To give any more advice I would need to have a better idea of exactly what you are trying to achieve.