Hi Rockie,
I assume you verified that your Tools, Application Options, Save dialog matches what I attached in my earlier email and tried opening the assembly?
You can attach zip files (have seen some jpgs also without a zip). Please use Pack and Go to zip up the assembly and all the files needed by it.
Pack and Go Help
Pack and Go is a tool that packages an Autodesk Inventor file and all of its referenced files in a single location. All files that reference the selected Autodesk Inventor file from a selected project or folder can also be included in the package.
Use Pack and Go to archive a file structure, copy a complete set of files while retaining links to referenced files, or isolate a group of files for design experimentation.
You can initiate Pack and Go from Microsoft Windows Explorer or from a Design Assistant session started outside Autodesk Inventor.
Thanks
shekar