Piwik v2.2.0 monitoring a WordPress blog (v3.8.2 using WP-Piwik v0.9.9.8). Stats seemed to be working (but not in agreement with Jetpack which is a separate issue) and have now stopped with the following error:
Error: The report ‘nb_pageviews’ was requested but it is not available at this stage. (Plugin ‘nb’ is not activated.)
Can anyone shed some light on what this error message is and how to correct the issue?