I have came across this error JCL ERROR CN(INTERNAL) once I submit my job

000100 //T03JOB1 JOB 1,NOTIFY=&SYSUID

000200 //STEP1 EXEC PGM=ONE

000300 //SYSUT1 DD DSN=&SYSUID..CW.DATA(T01),DISP=SHR

000400 //SYSUT2 DD DSN=&SYSUID..CW.OUTPUT(T01),DISP=SHR

000500 //SYSPRINT DD DUMMY

000600 //SYSIN DD DUMMY

000700 // IF RC EQ 0 THEN

000800 //STEP2 EXEC PGM=TWO

000900 //SYSUT1 DD DSN=&SYSUID..CW.DATA(T02),DISP=SHR

001000 //SYSUT2 DD DSN=&SYSUID..CW.OUTPUT(T02),DISP=SHR

001100 //SYSPRINT DD DUMMY

001200 //SYSIN DD DUMMY

001300 // ELSE

001310 // IF RC > 0 THEN

001400 //STEP3 EXEC PGM=THREE

001410 //SYSUT1 DD DSN=&SYSUID..CW.DATA(T02),DISP=SHR

001420 //SYSUT2 DD DSN=&SYSUID..CW.DATA(T02),DISP=SHR

001430 //SYSPRINT DD DUMMY

001440 //SYSIN DD DUMMY

001500 // ENDIF

001600 /*

000200 //STEP1 EXEC PGM=ONE

000300 //SYSUT1 DD DSN=&SYSUID..CW.DATA(T01),DISP=SHR

000400 //SYSUT2 DD DSN=&SYSUID..CW.OUTPUT(T01),DISP=SHR

000500 //SYSPRINT DD DUMMY

000600 //SYSIN DD DUMMY

000700 // IF RC EQ 0 THEN

000800 //STEP2 EXEC PGM=TWO

000900 //SYSUT1 DD DSN=&SYSUID..CW.DATA(T02),DISP=SHR

001000 //SYSUT2 DD DSN=&SYSUID..CW.OUTPUT(T02),DISP=SHR

001100 //SYSPRINT DD DUMMY

001200 //SYSIN DD DUMMY

001300 // ELSE

001310 // IF RC > 0 THEN

001400 //STEP3 EXEC PGM=THREE

001410 //SYSUT1 DD DSN=&SYSUID..CW.DATA(T02),DISP=SHR

001420 //SYSUT2 DD DSN=&SYSUID..CW.DATA(T02),DISP=SHR

001430 //SYSPRINT DD DUMMY

001440 //SYSIN DD DUMMY

001500 // ENDIF

001600 /*

I've probably made a ton of mistakes I just wish it would tell me where so I could rectify them

Also i'd appreciate it if you could point me in the direction of some good reading materials thanks