Piwik 1.12 Error

When I am in the “Actions->Titles” and click on “Open Row Evolution” -> opens modal window with this error:

There is an error. Please report the message (Piwik 1.12) and full backtrace in the Piwik forums (please do a Search first as it might have been reported already!).

Notice: Uninitialized string offset: 0 in /var/www/z-gu.ru/stat/plugins/CoreHome/DataTableRowAction/RowEvolution.php on line 78 

Backtrace -->

#0 Piwik_ErrorHandler(...) called at [/var/www/z-gu.ru/stat/plugins/CoreHome/DataTableRowAction/RowEvolution.php:78]
#1 Piwik_CoreHome_DataTableRowAction_RowEvolution->__construct(...) called at [/var/www/z-gu.ru/stat/plugins/CoreHome/Controller.php:175]
#2 Piwik_CoreHome_Controller->makeRowEvolution(...) called at [/var/www/z-gu.ru/stat/plugins/CoreHome/Controller.php:137]
#3 Piwik_CoreHome_Controller->getRowEvolutionPopover(...) called at [:]
#4 call_user_func_array(...) called at [/var/www/z-gu.ru/stat/core/FrontController.php:125]
#5 Piwik_FrontController->dispatch(...) called at [/var/www/z-gu.ru/stat/index.php:47]

Parameter label not set.

piwik from git (2bf8b29)

On the other server does not have this problem. On what exactly to look for how to understand why an error? What data are still needed to help me on the issue?

Can you reproduce on the demo ?

On demo.piwik.org this error does not appear.

It turns out, and I have this error occurs only on one of my sites (it was created in the database for a long time, but had a break for about a year in collecting statistics). Now collect statistics restored to the same database table (put the old id to the counter.) Maybe when upgrading the table is not refreshed at some point? How can we detect this error?

I am confused by the phrase “Parameter label not set.” About which parameter “label” referred to in this context?

Thank you.