windows - rundll32 from startup batch file causes "The specified module could not be found"

I'm trying to add the following command to a batch that runs on startup:

start C:\WINDOWS\system32\rundll32.exe C:\WINDOWS\system32\nvspcap64.dll,ShadowPlayOnSystemStart

but get the module not found error.

If I put the command in the registry Windows../Run it's fine, can also run it manually from the command line, so all the files are there.

Need to put it in the batch file because Nvidia decides periodically to delete the Windows../Run entry lol

I've tried cmd /c C:\WINDOWS\system32\rundll32.exe C:\WINDOWS\system32\nvspcap64.dll,ShadowPlayOnSystemStart

but didn't work. It's a batch file with lots of other stuff especially for programs that need long delays after boot, command still doesn't work after 2-3 min delays either.

maybe some better cmd parms could help??