The &C1ST symbolic is not causing the error.
The error is the result of 3 failed updates to ENHAEPGM -
ENHAEPGM *UPDATE ERROR* * TO UPRFX.UQUAL.SRCLIB, REPLACE EXISTING MBR.
*CANNOT EXPAND * TO SYS2.UQUAL.SRCLIB, REPLACE EXISTING MBR.
ENHAEPGM REPLACED * FROM UPRFX.UQUAL.SRCLIB, MEMBER APIU.
REPLACEMENT * FROM SYS2.CAI.ENDV.V180.SRCLIB, MEMBER APIU.
ENHAEPGM *UPDATE ERROR* * -- CHANGE UPRFX.UQUAL.SRCLIB TO A LIBRARY NAME THAT EXISTS
*CANNOT EXPAND * -- CHANGE SYS2.UQUAL.SRCLIB TO A LIBRARY NAME THAT EXISTS
ENHAEPGM *UPDATE ERROR* * -- ADD MEMBERS APIB, APIU AND APIR TO UPRFX.UQUAL.SRCLIB.
*CANNOT EXPAND * -- ADD MEMBERS APIB, APIU AND APIR TO SYS2.UQUAL.SRCLIB.
To locate the library the member is in, page up until you find the page heading that starts with 'BATCH JCL TAILORING AID ...'
The page heading identifies the data set being processed.
ENHAEPGM is located in the CSIQOPTN library:
BATCH JCL TAILORING AID VOL=N11001 DSNAME=SYS2.CAI.ENDV.V180.CSIQOPTN
All the errors in ENHAEPGM were to comment lines so not a problem that the lines were not updated.
If you want, you can manually edit ENHAEPGM and update the comment lines.