Cannot reply with Outlook Express 6

[chiefl]

I have Outlook Express 6 and when ever I attempt to reply to a message everything work fine until I Send/Receive mail. I get the sending message window and the blue indicator goes all the way to the right and stops there. The only way to clear the window is to halt the sending. If I start a new message to the same address everything works as advertised. Any ideas would be most welcome.
Jim