This issue was discussed here couple of times.
Outlook saves it's attachements into some temporary directory which is configurable. But problem is that this directory in default setup belongs into sandbox and virtual buble. So it means that only virtualized Outlook and applications in same bubble with Outlook see that directory and it's content. Applications from outside of virtual buble simply don't sees those files so it can not open/print/work with it.
http://communities.vmware.com/message/1400437#1400437
About those directories http://support.microsoft.com/kb/817878?wa=wsignin1.0