Hi DVB,
This error typically indicates that you're missing a dependency required for the SDK to run.
In this case it is rsync that's missing, you can install cwRsync which is free for Windows.
Once installed, open a Powershell window and type the following command to verify that rsync is installed properly
rsync --version
After you've done that, if you've exported the studio plugin from your community, you may need to export it again, then run li serve-sass to complete downloading any other core skin dependencies and precompile the skin to help with plugin validation when it comes time to submit it again.
I hope this helps
