Fatal error: Call to a member function getColumn() on a non-object

Support & Bugs
1

I hope, this is the right place to ask questions like this:
For three days, Piwik has been showing me in some widgets (“pages per visit”, “visitor countries” and “length of visit”) this error:

Fatal error: Call to a member function getColumn() on a non-object in /home/DOMAIN.TLD/hosts/DOMAIN.TLD/piwik/core/DataTable/Filter/Sort.php on line 120

Line 120 contains this:

$value = $row->getColumn($this->columnToSort);

If I choose in Piwik a timeframe to show, where there is no data to show, also the error doesn’t show. My PHP version is 5.1.6 and after the update to Piwik 0.6.1 some days/weeks ago, this error didn’t show up.
What does that mean and do you have tips to fix it?

Thanks a lot for your help!

2

Do you have any third party plugins installed that we should know about?

Do your web server logs havea more detailed error message (eg backtrace)?

3

Thanks for your answer.
The last week was very busy so that I couldn’t answer earlier. I don’t use any third-party-plugins for Piwik and unfortunately, my provider doesn’t log any php-error-messages. I will change that now.
Anyway, with the update to Piwik 0.6.2 this error has gone! Thank you for offering me help!