It seems that the "Confluence Basic Macros" Plugin did not get installed since it does not seem to be compatible with confluence 5.1 (See https://marketplace.atlassian.com/plugins/confluence.macros.basic )

This means that the {noformat} macro does not work in 5.1, and the same presumably applies to any other macros in the Basic Macros plugin.

See this post on Atlassian Answers: https://answers.atlassian.com/questions/155589/noformat-macro-not-working-after-update-to-5-1