The beginning of your environment doesn't have a matching end.
- Check to make sure you have spelt the name of the environment
You will get this error message if you do, say,
- Check that for every
\beginyou have a corresponding
\endwith the same name.
This book is also available as A4 PDF or 12.8cm x 9.6cm PDF or paperback (ISBN 978-1-909440-00-5).