You can always run the command ”$q” in any situation, that will list any command that you can run. Probably you have to issue an ”exit” or two in case a form has crashed. ”Finish” nearly always works too, that will shut down PDMS so you can start over.
It looks like you could just type a closing bracket, ")", to get to a more normal state. Do you know what you did when this happened? Did you run a macro? Open a form? Something else?
You can't copy & paste data from an excel sheet, but you still shouldn't get the messages you are getting. Weird, but the reason is that you are pasting data from Excel.