18B

Explanation
The common VTOC access facility (CVAF) encountered
one of the following conditions: A structure error in the VTOC index
The CVAF return code is not consistent with the CVAF status code.

System action
 A dump is written to SYS1.DUMP and an error record
is written to the logrec data set. The task is not ended. If CVAF
encountered a structure error in the VTOC index: Message IEC606I is issued.
CVAF disables the VTOC index.
If the caller of CVAF requests a read or write of a format 1 or
4 DSCB, CVAF performs the function and returns a code of yes to its
caller.
If the caller of CVAF requested a CVAF function that requires
the VTOC index, CVAF returns an error return code to its caller. This
may cause the caller to end.

 If the CVAF return code is not consistent with the CVAF status
code, CVAF returns an I/O error return code to its caller. This may
cause the caller to end.

System programmer response
  If the error recurs and the program
is not in error, search problem reporting data bases for a fix for
the problem. If no fix exists, contact the IBM® Support Center. Provide the logrec data set
error record and all printed output and output data sets related to
the problem.

Programmer response
If a structure error in the VTOC index was
encountered and the program ended, it may be rerun if it does not
depend upon the VTOC index. Run the IEHLIST utility to list the VTOC
and the disabled VTOC index. An inconsistency between the CVAF return
code and status code indicates a logic error in CVAF. You may not
be able to successfully run the job until the problem is corrected.

Source
DFSMSdfp