Does outlook just bring up the save dialog box as soo as you double-click on the attachment?
If so, go to Control Panel > Folder Options > File Types. Fint the file type in question and click advanced. Clear the "Confirm open after download" checkbox.
jbennet, I am assuming that some time in the past he unticked the box "Always ask before opening this type of file"
Going through Folder Options as per my previous post will bring back the very dialog you mention.
I thank you all for your suggestions and I have tried all the mentioned solutions but with no success. In the end I just repaired outlook with another copy and everything seems to be working properly. I believe the copy I was using was corrupt some how.