private void validateFieldType( char ftype )
	{
	boolean valid = (("CNFDLMG").indexOf(ftype)>=0);
	valid = valid || ( (!DOS_FOX) && (("IBTY0").indexOf(ftype)>=0) );
	if(!valid)
		try { throw new IOException ("What a field type is " + ftype + " ?"); }
		catch (IOException e) { e.printStackTrace();
		}
	}