Upgrading SA 6.9 to SA 8 and using the CLI tool results in error:

So recently upgraded from SA 6.9.0.114 to  SA 8.0.2.4779. When trying to use the command line tool to build the obfuscated projects this error occurs all of a sudden:

"C:\Program Files\Red Gate\SmartAssembly 8\SmartAssembly.com" /build "D:\_work\1\s\src\Resources\Obfuscation\RLI.CFS.Web.Proxy.IIS.saproj" /input="D:\_work\1\s\src\CFS\RLI.CFS.Web.Proxy.IIS\bin\Obfuscation\RLI.CFS.Web.Proxy.IIS.dll" /output="D:\_work\1\s\src\CFS\RLI.CFS.Web.Proxy.IIS\bin\Obfuscation\RLI.CFS.Web.Proxy.IIS.dll"
<div><div></div></div><div><div>    38>RLI_DoObfuscation:
</div></div><div><div></div></div><div><div>         SmartAssembly v8.0.2.4779 Evaluation
</div></div><div><div></div></div><div><div>         Copyright c Red Gate Software Ltd 2005-2021
</div></div><div><div></div></div><div><div>         
</div></div><div><div></div></div>         System.ArgumentException : The path is not of a legal form<br>

What might be going on here?

Thanks!