When I try to use the component wizard to add "dxmasf.dll", I get blown completely out of the Author 3.0 environment. I can successully add other TLBs and OCX files with the Component Wizard. This file is from the latest Hotfix for Windows Media Player.
Tony, thanks for submitting the problem report. We were able to reproduce the problem. As a workaround have you tried creating the component manually? I was able to create a new component and add a file without problems.