1) Updated to Akeeba CMS Update 1.0.a2
2) Added rule administrator/components/com_cmsupdate/restore.php to .htaccess
Update to Joomla! 2.5.18 worked correctly after that but mentioned warning where shown (see attached)... Where this file is located to be deleted manually? How to solve or round mentioned issue when updating several others?
BTW, To attach an small *.png or *.zip file to this ticked is not being allowed. Follow this link to see mentioned screenshot: http://l.js2go.net/1bCDp37. Take care!
Hope this helps,
Rgrds,