The newest Magento Security Patch SUPEE-5994 has .sh extension and can be applied within command sh PATCH_SUPEE-5994_CE_188.8.131.52_v1-2015-05-15-04-34-46.sh
But if you don’t have ssh access to your Magento website you can use our github version of files which already patched for Magento version 184.108.40.206.-220.127.116.11. You can view & download patched files for 18.104.22.168 at this link.
Few days ago Magento send message to update all community editions to the latest security patches.
Here is the Github diff of files in case you cannot update it using SSH or don’t have it.
The version of Magento Security Patch SUPEE 5344 and 1533 applied for Magento 1.8.x-1.9.x
The issue admin 404 page not found usually appears when database was moved and it loses integrity keys. Also it may happened when you migrate website to different hosting.
You will not notice that issues exist until you will try to login to magento admin page. The magento admin 404 page not found issue will be shown in this case.
The issue will show admin 404 page not found and it doesn’t mean that this page not exist. if you will check Magento admin log ( you can find it at the magento root folder var/log/system.log ) you will see lines which reporting this issue.