I looked at earlier tickets that looked like they addressed this, but did not find a solution (the fixes should be included in 1.12).

One notable detail is that the server is running PHP 5.4.13. This caused other issues on a related website (the website being tracked).

The error message is below:

Notice: Array to string conversion in /var/www/vhosts/new-example.com/httpdocs/core/DataTable/Renderer/Csv.php on line 283

Backtrace -->
#0 Piwik_ErrorHandler(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/DataTable/Renderer/Csv.php:283]
#1 Piwik_DataTable_Renderer_Csv->renderDataTable(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/DataTable/Renderer/Csv.php:132]
#2 Piwik_DataTable_Renderer_Csv->renderTable(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/DataTable/Renderer/Csv.php:68]
#3 Piwik_DataTable_Renderer_Csv->render(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/API/ResponseBuilder.php:193]
#4 Piwik_API_ResponseBuilder->getRenderedDataTable(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/API/ResponseBuilder.php:300]
#5 Piwik_API_ResponseBuilder->handleDataTable(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/API/ResponseBuilder.php:77]
#6 Piwik_API_ResponseBuilder->getResponse(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/API/Request.php:147]
#7 Piwik_API_Request->process(...) called at [/var/www/vhosts/new-example.com/httpdocs/plugins/API/Controller.php:25]
#8 Piwik_API_Controller->index(...) called at [:]
#9 call_user_func_array(...) called at [/var/www/vhosts/new-example.com/httpdocs/core/FrontController.php:125]
#10 Piwik_FrontController->dispatch(...) called at [/var/www/vhosts/new-example.com/httpdocs/index.php:47]

Keywords: CSV, Visitor Log