The "Incompatible qualifiers" is because COBOL does not allow the SIGN clause for other than DISPLAY usage. ACUCOBOL ignores this error.
The "illegal precedence" is because if any symbols after the decimal point are Z, then all the symbols after the decimal point must be Z. Again, ACUCOBL ignores this nonsensical PICTURE character-string and treats it as if all the symbols after the decimal point were Z.