I was attempting to use some vb.net code in a vbs file and was getting "The system cannot find the file specified." on the CreateObject line. I tracked it down to the way I registered the DLL.
One sugestion told me to unregister and re register it with regsvr32. Because I was using .NET, I knew that was not it. It turned out to be my use of regasm to register my DLL. I left out the /CODEBASE option.
Once I registered it with that option, the error went away.