When you reach the end of a source line in the DBD you must put a comma after the last operand and a C in column 72.

Here's part of a DBD for example:

       DBD     NAME=BSEP0C,ACCESS=(HIDAM,OSAM),                        C
               REMARKS='RBA PROJECT GROUP 4 -- ADD SEQNUM UNIQUE KEYS TC
               O SSE014 AND SSE147 SEGMENTS.  ADD 8-BYTES MORE FILLER.'
***********************************************************************
*        DATASET GROUP NUMBER 1                                       * 
*********************************************************************** 
DSG001 DATASET DD1=DSEP00C,SIZE=(8192),SCAN=255,FRSPC=(6,30)            
*********************************************************************** 
*        SEGMENT NUMBER 1                                             * 
*********************************************************************** 
       SEGM    NAME=SSE001,PARENT=0,BYTES=129,RULES=(PPP,LAST),        C
               PTR=(TWINBWD,,,CTR,),COMPRTN=(HDCXITSE,DATA,INIT)        
       FIELD   NAME=(SSE001KY,SEQ,U),START=1,BYTES=9,TYPE=C             
       FIELD   NAME=(/SX006),START=1,BYTES=4                            
       FIELD   NAME=(SECSN),START=112,BYTES=10,TYPE=C                   
       FIELD   NAME=(TRKGSTAT),START=123,BYTES=1,TYPE=C                 
       LCHILD  NAME=(SSEHIX,BSEI0C),PTR=INDX,RULES=LAST                 
       LCHILD  NAME=(SSESEA),PTR=NONE,PAIR=SSESEB,RULES=LAST            
       LCHILD  NAME=(SGESEB,BGEP0C),PTR=NONE,PAIR=SSEGEB,RULES=LAST     

Only the DBD and SEGM lines were long enough to continue with C in 72.