Thank you, dadreamer! There is, in fact, a dependency on cvirte.dll, which is installed on my development host, but not on the deployment host. I tried installing RTE 5.5, but it would not run on Windows 10, no matter what compatibility settings I pick (I tried all options back to Win 95). So, instead, I matched the version of the cvirte on the development machine (19.0. ...), not of the vendor's code, and voila!