Abhishek Vijayakumar You only included the .ASM file in your ZIP file. The ASM file only contains the information about the assembly, its components and their relationships. If you do not included the components, no one can open the assembly.
From Creo Parametric, pick File, Save As, and change the File Type to ZIP (last item in the list). This will save a complete archive of the open model as a ZIP file.