Try these two options:
1 - Go to the bottom of this page and click on the "Delete Cookies" button:
http://www.mousescrappers.com/photos...action=cookies
2 - If option #1 doesn't work, try logging in from here:
http://www.mousescrappers.com/photos/adm-index.php (it will throw an error that says you don't have rights, but it may log you in anyway)
Be sure to scroll down the page until you see the special login area