I select "ArduinoISP" as the programmer. I press "Burn Bootloader". I get the following: avrdude: Error: Could not find USBtiny device (0x2341/0x49) Error while burning bootaloader.

The first problem is that you need to select Arduino as ISP from the Tools > Programmer menu. ArduinoISP is a dedicated in system programmer made by Arduino, confusing because the name of the sketch used with Arduino as ISP is ArduinoISP.

The next problem you'll likely encounter is that ATmega32U4 based boards can't be used for Arduino as ISP. The cause of this is explained at https://petervanhoyweghen.wordpress.com/2012/09/16/arduinoisp-on-the-leonardo as well as a solution. Unfortunately the solution described in that blog post no longer works as-is with recent versions of the Arduino IDE. I have updated the solution to work with recent Arduino IDE versions and added support for installation via Boards Manager here: https://github.com/per1234/ATmega32U4asISP

I select "ArduinoISP" as the programmer. I press "Burn Bootloader". I get the following: avrdude: Error: Could not find USBtiny device (0x2341/0x49) Error while burning bootaloader.

You need to select Arduino as ISP from the Tools > Programmer menu. ArduinoISP is a dedicated in system programmer made by Arduino, confusing because the name of the sketch used with Arduino as ISP is ArduinoISP.

If you're using Windows you'll also likely encounter the issue that ATmega32U4 based boards can't be used for Arduino as ISP. The cause of this is explained at https://petervanhoyweghen.wordpress.com/2012/09/16/arduinoisp-on-the-leonardo as well as a solution. Unfortunately the solution described in that blog post no longer works as-is with recent versions of the Arduino IDE. I have updated the solution to work with recent Arduino IDE versions and added support for installation via Boards Manager here: https://github.com/per1234/ATmega32U4asISP