1 - What error? Show it.
2 - REMOVECC, I believe, stands for REMOVE Carriage Control i.e. remove any printer control characters in column 1. The rest I do not know well enough to say but I m not going to look up the manual because you can do that yourself.
REMOVECC - as NicC says
NODETAIL - don't show detail lines, only HEADERn/TRAILERn lines
SECTIONS - define a section of a report, based on a control field, with HEADER3/TRAILER3 available
BUILD - I'm sure you know. I don't think it is necessary here (make that part of your investigation and let us know)
Gerry defined a GROUP with an ID, and the report produced (SECTIONS is a reporting feature, as are HEADERn/TRAILERn, hence the Printer Control Character in the first place) is your output file of "total lines". The TRAILER3 record simply contains bytes from position 16 for a length of 54 from the last record in the group..