Ah, thank you! I had forgoten all about YAPE::Regex::Explain.
The capturing parentheses are needed to pass the expression to a different function.
What is the error message?
I'm not entirely sure yet why it's throwing an error. It's an internal error check with Net::Telnet. After much debuging I've determined errmode->mode is being set to die after passing this regex to the prompt method. This causes another function, error(), to exit the script with die, but it doesn't print the error message. I was hoping maybe there was something I was missing with the regex causing the behavior