Could you mention the exact Magento version you are using?
Your question headline mentions 188.8.131.52 and the content section mentions 184.108.40.206.
Both versions have separate patches.
220.127.116.11 SUPEE-7405 for CE 18.104.22.168-22.214.171.124
126.96.36.199. SUPEE-7405 for CE 188.8.131.52-184.108.40.206
Check if you have downloaded the correct version of patch. If you have applied the correct patch try to clear var/cache and var/session folder then login.
Also refer this link http://magento.stackexchange.com/questions/98220/security-patch-supee-7405-possible-problems