Xerox 721 Message Manual page 239

SUMMARY SHEET ERROR MESSAGES
Invalid operator ordering; SHOW precedes first font set.
No family has been set up in the Interpress master prior to text
imaging.
Invalid type for argument(s) of operator: <operatorName>.
In processing an Interpress operator, the required operand type
was not found on the stack.
Invalid argument(s) value for operator: <operatorName>.
An invalid value for the operator was found.
Master not well-formed; bad document header.
The Interpress header, "Interpress/Xerox/n.0..." was not found in
a file that required one. The file is either the Interpress master or
an SIF. A SIF problem is preceded by the error "Master Warning
(page n): Problem with insert file: "fileType>fileName.""
Master not well-formed; imaging operator <operatorName>
found in preamble.
One of the MASK operators was encountered in the preamble;
MARK Recovery occurs as a result of the master error.
Nested rendered characters not supported.
A character within the LPS font contains multiple levels of
rendered character nesting.
Action Recreate the font by keying in the IFU ADD command and
eliminating the nested rendered characters by using the
COMPOSITE option.
Operator not implemented: <operatorName>.
A Professional Graphics operator not supported on the LPS was
found in the master.
Page blank due to errors.
Refer to prior messages for the cause of the blank page.
Page printing curtailed due to errors.
MARK Recovery was not attempted due to the severity of the
error or MARK recovery failed.
Parse failure; bad length for operand: <operatorName>.
An operand length exceeds the minimums described in the
Interpress standard.
XEROX 4635 LASER PRINTING SYSTEM MESSAGE GUIDE 14-15