Logger allows for a NO_OP installation which means that when installed in NO_OP mode all the calls to it will just run a null statement. This is typically used in production systems where, for various reasons, you may not want to actually run Logger. Note: this is not the recommended approach since running Logger in Error mode is better as it will still log.
The NO_OP installation only installed the package spec and body. This may have caused some errors as the package itself references the Logger tables. Code in applications calling logger may have also referenced the other Logger objects.
Starting in 3.1.0, the NO_OP installation will install all Logger objects so that code that worked in a development environemnt with the full version of Logger will still compile and run in a NO_OP version. It just won't log any information. To read more about the decisions around these changes please review Issue 78.