Outlook hangs trying to move the attachment from one line to other

Hi, I am facing a issue in outlook while using attachments. Outlook is working fine since a year and I know the basic of outlook as such. The situation is this: Whenever there are multiple attachments in the mail which I am composing, I cannot reorder the files. If I cut a file so that I can paste in a different location in the compose mail window, entire outlook hangs, it tries to restart after manually trying to close and then it takes about 10 minutes or so and tells that there was an error and I have perform the mail action again. What might b causing this problem?
