Yahoo Mail "iphone crashes" Questions

Yahoo Mail on iPhone 3G causes Mail app to crash Y!Mail causes my iPhone 3G mail application to crash and return to the home screen every time Y!Mail account is turned on. I tried accessing Y!Mail ...

...iphone 3gs.everytime i put in the correct details amessage comes on the screen saying...............the username or pass word for imap.apple.mail.yahoo.com is incorrrectbut i know it is correct coz i ...