Well, as the popup describes it quite stratightforward, the agent for virtual desktops does not support web automation. You cannot do web automation via RDP.
My suggestion would be that you do move the web part to your local desktop, if you can do that.
Alternatively, you can try to install the full PAD package on the virtual machine and run the whole flow there, if you are allowed to do that.
If neither of those is an option, you will need to resort to sending mouse clicks, keystrokes and using image recognition.