It means that someone was trying to guess her password and exceeded the number of trials permitted by Hotmail, so the account was locked out for 24 hours in order to protect it.
Try this site to see if she's blocking you:
http://www.msnstatus.com/
Or go to this site, and follow the instructions.
Then you'll be ale to send an e-mail and you may know if she open it, when did she open it, where did she open it, how many times did she read it, how many time did she spent reading your e-mail, was your e-mail forwarded...
http://www.readnotify.com/