error in grammar

Hello,

in:
https://github.com/paule32/dBase4Linux/blob/master/source/parser/dbase/yymain.cc

I get the error in line 626:

 1.
    /dbase/source/parser/dbase/yymain.cc:626: Error: no match for
    'operator[]' (operand types are 'char' and 'const type {aka const
    boost::phoenix::actor<boost::proto::exprns_::expr<boost::proto::tagns_::tag::assign,
    boost::proto::argsns_::list2<boost::proto::exprns_::expr<boost::proto::tagns_::tag::terminal,
    boost::proto::argsns_::term<boost::spirit::attribute<0> >, 0l>,
    boost::phoenix::actor<boost::proto::exprns_::basic_expr<boost::phoenix::tag::construct,
    boost::proto::argsns_::list4<boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal,
    boost::proto::argsns_::term<boost::phoenix::detail::target<dBaseParser::expression_ast>
     >, 0l>,
    boost::phoenix::actor<boost::proto::exprns_::basic_expr<boost::phoenix::tag::construct,
    boost::proto::argsns_::list2<boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal,
    boost::proto::argsns_::term<boost::phoenix::detail::target<std::__cxx11::basic_string<char>
     > >, 0l>,
    boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal,
    boost::proto::argsns_::term<const char*>, 0l> >, 2l> >,
    boost::phoenix::actor<boost::proto::exprns_::basic_expr<boost::phoenix::tag::construct,
    boost::proto::argsns_::list2<boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal,
    boost::proto::argsns_::term<boost::phoenix::detail::target<std::__cxx11::basic_string<char>
     > >, 0l>, boost::phoenix::actor<boost::spirit::argument<0> > >, 2l>
     >,
    boost::phoenix::actor<boost::proto::exprns_::basic_expr<boost::phoenix::tag::construct,
    boost::proto::argsns_::list2<boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal,
    boost::proto::argsns_::term<boost::phoenix::detail::target<std::__cxx11::basic_string<char>
     > >, 0l>,
    boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal,
    boost::proto::argsns_::term<const char*>, 0l> >, 2l> > >, 4l> > >,
    2l> >}')
 2.
    >>  ')' [
 3.
    ^


How can I fix this error?

TIA
Jens

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