Entry Point Not Found

When I attempt to run mygame.exe, following popup was showed :

:’(
so…what should I do?

update/re-instal DX?
or delete this file and get a new one from a dx pack

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.