Piwik 2.9.1 Array to string conversion in TrackerCodeGenerator.php (no replies)

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<strong>There is an error. Please report the message (Piwik 2.9.1)
and full backtrace in the <a href='?module=Proxy&action=redirect&url=http://forum.piwik.org' target='_blank'>Piwik forums</a> (please do a Search first as it might have been reported already!).<br /><br/>
Notice:</strong> <em>Array to string conversion</em> in <strong>/home/user/public_html/piwik/core/Tracker/TrackerCodeGenerator.php</strong> on line <strong>137</strong>
<br /><br />Backtrace --&gt;<div style="font-family:Courier;font-size:10pt"><br />
#0 Piwik\Error::errorHandler(...) called at [:]<br />
#1 str_replace(...) called at [/home/user/public_html/piwik/core/Tracker/TrackerCodeGenerator.php:137]<br />
#2 Piwik\Tracker\TrackerCodeGenerator->generate(...) called at [/home/user/public_html/piwik/plugins/SitesManager/API.php:93]<br />
#3 Piwik\Plugins\SitesManager\API->getJavascriptTag(...) called at [:]<br />
#4 call_user_func_array(...) called at [/home/user/public_html/piwik/core/API/Proxy.php:211]<br />
#5 Piwik\API\Proxy->call(...) called at [/home/user/public_html/piwik/core/API/Request.php:216]<br />
#6 Piwik\API\Request->process(...) called at [/home /user/public_html/piwik/plugins/API/Controller.php:33]<br />
#7 Piwik\Plugins\API\Controller->index(...) called at [:]<br />
#8 call_user_func_array(...) called at [/home/user/public_html/piwik/core/FrontController.php:582]<br />
#9 Piwik\FrontController->doDispatch(...) called at [/home/user/public_html/piwik/core/FrontController.php:96]<br />
#10 Piwik\FrontController->dispatch(...) called at [/home/user/public_html/piwik/core/dispatch.php:36]<br />
#11 require_once(...) called at [/home/user/public_html/piwik/index.php:46]<br />
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