If it is not 0n a Network Drive that is backed up I'd say your project is toast.
It sounds like someone deleted it or overwrote your file.
If I were to save VBA project inside my inventor files I'd probably think hard about making them template files and read only.
I do not use that method because I set a default global VBAProject file in Inventor's Options | Files tab. I make sure it is on our network and backed up..
ALL files have access to these kind of projects/
I'd guess some of us will have the same problem with embedded iLogic unless we backup the part templates they reside in.