The problem here is that you are setting the DIALECT"ENTCOBOL" on which also turns on CHARSET"EBCDIC" and you are trying to read an ANSI file.
Did this use to work in a previous version of COBOL?
If these sequential files are actually line sequential files with CRLF separating the records then you could try setting the compiler directive SEQUENTIAL"LINE" as then the compiler will treat files specified with ORGANIZATION SEQUENTIAL as if ORGANIZATION IS LINE SEQUENTIAL were specified.
Files specified as LINE SEQUENTIAL will be treated as ANSI files by default.
Thanks.