using outlook webaccess

We use outlook web access when out of the office to check email etc. In the past we have been able to send attachments by creating a message, going to the attachment tab, browsing for the file and clicking add. The attached message shows up on a list at the bottom of the screen. Now when I do this, you see the file being transfered, but when it completes there is nothing in the list, and if you send it, no attachments get transmitted. Has anyone run into a problem like this before? Thanks for your help