NAT5100: on-form: ".EL" WITHOUT PRECEDING ".IF".

NAT5101: on-form: ".EI" WITHOUT PRECEDING ".IF".

NAT5102: on-form: ".EL" WITHOUT PRECEDING ".TH".

NAT5103: on-form: ".EI" EXPECTED BUT NOT RECEIVED.

NAT5104: on-form: INVALID NESTING OF ".HL" STATEMENTS.

NAT5105: on-form: INVALID NESTING OF ".BL" STATEMENTS.

NAT5106: on-form: INVALID OR MISSING OPERANDS IN ".VD" STATEMENT.

NAT5107: TEXT VARIABLE SPECIFIED MORE THAN ONCE IN ".VD" STMTS.

NAT5108: on-form: FORMAT ERROR IN ".VD" CONTROL STATEMENT.

NAT5109: on-form: INVALID OR MISSING POS IN ".VD" STATEMENT.

NAT5110: on-form: INVALID OR MISSING LEN IN ".VD" STATEMENT.

NAT5111: on-form: INVALID OR MISSING CONDITIONAL OPERATOR.

NAT5112: on-form: ".AN" WITHOUT PRECEDING ".IF".

NAT5113: on-form: ".OR" WITHOUT PRECEDING ".IF".

NAT5114: on-form: ".EW" WITHOUT PRECEDING ".WH".

NAT5115: on-form INPUT LINE TOO LONG; HAS BEEN TRUNCATED.

NAT5116: on-form: ".WH" MAY NOT BE SPECIFIED WITHIN ".IF" BLOCK.

NAT5117: on-form: INVALID NESTING OF ".WH" STATEMENTS.

NAT5118: on-form: VALUE EXCEEDS MAXIMUM LINE LENGTH.

NAT5119: on-form: ".EW" MISSING WHEN FORMATTING TERMINATES.

NAT5120: on-form: INVALID KEYWORD IN ".OP" STATEMENT.

NAT5124: on-form"S WORK POOL IS TOO SMALL.

NAT5126: on-form: MAXIMUM OF 30 TEXT VARIABLES IN ".VD".

NAT5127: on-form: RECURSIVE NESTING OF INPUT SOURCES NOT ALLOWED.

NAT5128: on-form: NO TABULATOR SETTINGS ACTIVE.

NAT5129: on-form: RESTORE (.RS) WITHOUT PRECEDING SAVE (.SA)

NAT5130: on-form: INVALID ".TB" CONTROL STATEMENT.

NAT5131: on-form: INVALID OPERAND IN ".PN" CONTROL STATEMENT.

NAT5132: on-form: INPUT BUFFER OVERFLOW DURING VARIABLE SUBSTIT.

NAT5133: TEXT VARIABLE NOT PREVIOUSLY DEFINED.

NAT5134: on-form: ".XF" STATEMENT WITHOUT PRECEDING ".TF".

NAT5135: TEXT ELEMENT COULD NOT BE FOUND.

NAT5136: NO TEXT VARIABLE NAMES SPECIFIED IN ".XF" STATEMENT.

NAT5137: on-form: TARGET LABEL FOR .GO STATEMENT NOT FOUND

NAT5138: on-form: .GO NOT ALLOWED OUTSIDE MACRO DEFINITIONS

NAT5139: THERE TOO MANY TEXT VARIABLES DEFINED.

NAT5140: on-form: CONTROL STATEMENT IS NOT (YET) IMPLEMENTED.

NAT5142: on-form: MAXIMUM HIERARCHY LEVEL IN T.O.C. EXCEEDED.

NAT5143: on-form: INVALID PARAMETER VALUE IN ".CH" STATEMENT.

NAT5144: on-form: MAXIMUM LENGTH OF AN INDEX ENTRY EXCEEDED.

NAT5149: on-form: INVALID SEQUENCE OF CONTROL STATEMENTS.