UNO R3 ISP trouble (ATtiny45)

I don't understand what you mean by this. Could you dumb it down a little? I'm sorry, like I said I'm new to this. I tried changing the name of the file and it just added the .c back on the end.

I loaded avrdude and verified that Arduino is one of the supported ISP's and ATtiny45 is a supported microcontroller so I don't think that is the problem, but when I enter the command to burn the hex file I get an error:

Roberts-MacBook-Pro:~ robertwinter$ avrdude -c arduino -p t45 -U flash:w:firefly.hex
avrdude: ser_open(): can't open device "unknown": No such file or directory
ioctl("TIOCMGET"): Inappropriate ioctl for device

avrdude done. Thank you.

Any ideas? Thanks!!!