Bad Request Your browser sent a request that this server could not understand. Size of a request header field exceeds server limit.
Cookie: __utma=40161215.1118858552.1225984368.1226006917.1227714374.3; __utmz=40161215.1225984368.1.1.utmccn=(direct)|utmcsr=(direct)|utmcmd=(none); __utmb=40161215; __utmc=40161215; PHPSESSID=le231lcl5ui53obiif041rk954; piwik-auth=login%3DdGlsbA%3D%3D%3Atoken_auth%3DZTQwYjY3Y2MwNTM0OWYzZmZmNWI3YjUwM2MzYWZjOTA%3D; piwik_visitor3=1%3DY2QwZTZhY2VkOGQ1NzYyOWVhMmU5YzhmM2IwNDg5Zjc%3D%3A2%3DMTIyNzcxNDg5Ng%3D%3D%3A3%3DMTIyNzcxNDg5Ng%3D%3D%3A4%3DMg%3D%3D%3A5%3DNA%3D%3D; piwik_visitor2=1%3DYjQ5NjRmODU3N2Y4YmE5NTcwZjMxMjliNGUyODllNTU%3D%3A2%3DMTIyNzcxNDkwNw%3D%3D%3A3%3DMTIyNzcxNDkwNw%3D%3D%3A4%3DMw%3D%3D%3A5%3DNA%3D%3D; piwik_visitor4=1%3DMWQ1ZTA3YjRhMjI3ODEwMTNlMWQ5NmMxZjI3YTE5Yzc%3D%3A2%3DMTIyNzcxNDk5MA%3D%3D%3A3%3DMTIyNzcxNDk5MA%3D%3D%3A4%3DNA%3D%3D%3A5%3DNA%3D%3D; piwik_visitor5=1%3DNTVmMDkxYTM4ZTBmMWY5ZDhlNzJhNmRjY2IxZjMzYjM%3D%3A2%3DMTIyNzcxNTE3NA%3D%3D%3A3%3DMTIyNzcxNTE3NA%3D%3D%3A4%3DNg%3D%3D%3A5%3DNA%3D%3D; piwik_visitor6=1%3DMGNkNTBkNzBkYjI2YTIyZTFmNmJlOGVjYmQ5YjQ2ZWU%3D%3A2%3DMTIyNzcxNTM2Ng%3D%3D%3A3%3DMTIyNzcxNTM2Ng%3D%3D%3A4%3DNw%3D%3D%3A5%3DNA%3D%3D
There are a few fixes to this - one is to up the size of the request header, which is what I did when I noticed the same error on OpenX. ;-) However, it would be nice if someone implemented a workaround in Piwik in the future.
Just a general note - no idea if you guys have notification on your trac, but in case you need feedback, I put my email address on my trac account.