Files not attaching to email or other sites in safari on iMac

When I try to attach a file to email or upload files to different internet sites, Outlook/Safari crashes and a Problem Report notification pops up saying that "Mail quit unexpectedly" or "Safari quit unexpectedly".

This occurs whether I am uploading through the Outlook app, through Hotmail via Safari, or uploading to other sites (for example, when uploading a file to seek.com).

This is very frustrating as I need to attach files to email for work. i am using an iMac, Mac OS X 10.Please help!