Unclear referee's message
The message is vague, but check the text the referee has highlighted. Chances are you can see something wrong. The word "typeset" here could indicate a typesetting error - for example, perhaps you forgot to include a reference that the text cites (this makes LaTeX go [??]). Or it could just mean there's a spelling error, an ambiguous sentence, etc.

Either way, the reviewer pointed out which lines they're referring to, which should help you solve the issue.