I'd say if you can enter the directory (both DO and GLOBAL do, right?) try to execute the command. Buf either way, definitely don't bounce out of the loop.The preprocessor (aliases, variables, redirection, etc.) is returning an error with the mismatched back quotes.
So the question is -- do you want to ignore the error (and the fact that the preprocessor hasn't done anything with the line) and try to blindly execute a command, or skip that line?