Hi Ken - I'm testing an upgrade shortly with a 4.9.3 site and based on that error, I would assume you've used an upgrade build.
I found that in the past, sometimes files were omitted out of the upgrade build that, while not need when based on one or two versions behind, were missing in other earlier versions of DNN that might not have been tested that far back.
I hope I'm not sounding too confusing, it's hard to explain, but in a nutshell, why don't you try the upgrade again by using the install build instead.
Over the last couple of years, I will generally look how far back the dnn build is that I'm going to be upgrading and I upgrade using the source files because I have found that most of these errors have been caused by files in the 'upgrade' build were never in the previous builds to start with. I think this would be more apparent in builds that had known issues,and changing from one number to another, eg.. when we upgraded from DNN 2 > 3 we'd use the full install, when upgrading from 3 > 4 the same and that is how I have been preparing my upgrade I hope to do on dnnskins from dnn 4 > 5 by using a full install download rather than upgrade.
I hope this clarifies it, but the log is basically say - hey I can't find the file to put on the page, which perhaps could mean the module does not exist.
It's not a guaranteed solution but something I've found has worked for me in some cases.
Nina Meiers