Abend 878000 hex occurred processing command 'EXEC '.

"Abend 878000 hex occurred processing command 'EXEC '." This error message occurs while executing REXX when there is insufficient virtual storage.

Possible solutions:

• Check if you are using EXECIO * DISKR. In this case, the input data might be too large which may cause allocation error. 

          To avoid this error, execute the same REXX in background mode using JCL with maxium                    REGION parameter value. 

• Try logging out of the session, login again and execute the REXX again.