log on to admin page is not working brings you to error page. need help

[kenandjen22]

Can anyone help with this problem. web site is working. But can not sign on to admin page. The error code that is coming up is "file does not exist".  I have never had this problem before. This is an online retail store. I am unable to sign in to edit product stock, check orders, etc. !  since 4/19/13. Please help...

[abantecart]

Open file system/logs/error.txt and grab last few lines after you try to login to admin.

Please post the error you get here.

We need to see exact error you get.