189: Unexpected character in metadata name
A line in your document starts with a squirrel @, which marks a metadata declaration. A metadata declaration assigns a value to a metadata name. A metadata name may consist of letters, digits, hyphen and non-ASCII characters. In your case it contains whitespace or one of the characters ! " # $ % & ' ( ) * + , . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~, which is not allowed.
Solution
Choose a metadata name that only consists of letters aโz, AโZ, digits 0โ9, the hyphen - or characters outside the ASCII range like umlauts รค and emoticons ๐งธ. Metadata names with a recognized meaning can be found on the metadata page.
If you did not mean to declare metadata, but want to use a previously declared metadata name at the start of a line, you can enclose it in backticks so that the squirrel @ is not the first character in the line anymore:
`@author` wrote this.
If you did not mean to do anything related to metadata, but want to use a literal @ at the start of the line, prepend a backslash: \@