Step to disable the “Send File ” (file transfer) option in Yahoo messenger 11.

Edit the “res_msgr.dll” and disable the “Send File” option.

Steps:
1.      edit  res_msgr.dll  using ‘PE explorer ‘. (download 'PE explorer' from www.heaventools.com)
       
       2.      click on View -> Select ‘Resources’ -> select 'Menu' from drop down -> under 'menu', Select 
"431" and double click on '431' -> which pops a dialog where you get a option to 'deselect'  "Send file" option

Info:
1.       Event ‘431’ is responsible for “Send File” functionality.
2.      when we select "431"  and look at the right side panel for script, under which "Action" function is scripted for    "Send Files"  (deselecting the 'Send Files' option will edit the script/Code as ("SEND FILE"= "INACTIVE")