Error Status Codes:

There are various ways to trap errors in a RPG program like, Operation code extender, MONITOR, INFDS and *PSSR. Once the program has trapped the error, but which error is it? The %STATUS BIF provides a five-digit status code that tells you what the error is. Program Status Codes are in the range 00100 to 00999 and File Status Codes are in the range 01000 to 01999. Status Codes in the range 00000 to 00050 are considered to be Normal (i.e. they are not set by an error condition).
Status codes correspond to RPG Run time messages file in QRNXMSG (e.g., Message RNQ0100 = Status Code 00100). You can view the messages using the command:
DSPMSGD RANGE(*FIRST *LAST) MSGF(QRNXMSG) DETAIL(*BASIC)
The below table lists some of the more commonly used Status Codes.
00100 Value out of range for string operation
00102 Divide by zero
00112 Invalid Date, Time or Timestamp value.
00121 Array index not valid
00122 OCCUR outside of range
00202 Called program or procedure failed
00211 Error calling program or procedure
00222 Pointer or parameter error
00401 Data area specified on IN/OUT not found
00413 Error on IN/OUT operation
00414 User not authorized to use data area
00415 User not authorized to change data area
00907 Decimal data error (digit or sign not valid)
01021 Tried to write a record that already exists (file being used has unique keys and key is duplicate, or attempted to write duplicate relative record number to a subfile).
01022 Referential constraint error detected on file member.
01023 Error in trigger program before file operation performed.
01024 Error in trigger program after file operation performed.
01211 File not open.
01218 Record already locked.
01221 Update operation attempted without a prior read.
01222 Record cannot be allocated due to referential constraint error
01331 Wait time exceeded for READ from WORKSTN file.