The SHUNCHAR keyword in the SGML Declaration must be followed by the keyword NONE, by the keyword CONTROLS or by at least one character number to be shunned.

#0108   Markup Error

ISO 8879, 13.4.2

The SHUNCHAR keyword in the SGML Declaration must be followed by the keyword NONE, by the keyword CONTROLS or by at least one character number to be shunned.