The compiler did not find a closing apostrophe at the end of a character string. 

Note that character strings cannot be continued onto the next line - however, you can use the '+' operator to concatenate two character strings on separate lines.

program Produce;

begin
  Writeln('Hello world!);   (*<-- Error message here -*)
end.

We just forgot the closing quote at the string - no big deal, happens all the time.

program Solve;

begin
  Writeln('Hello world!');
end.

So we supplied the closing quote, and the compiler is happy.