The action "Watch Me Do" encountered an error. The operation couldn’t be completed. (OSStatus error -50.)

Watch Me Do is designed to replay the same mouse click and keyboard events at the same speed. Think of driving your car to work and recording each turn and stop. Then replay each turn and stop at the same speed. What if during the replay the traffic is moving slightly faster or slightly slower? If you drive the same route to work you might get a red light at an intersection that you had a green light at yesterday. "Watch Me Do" doesn't know how to deviate from these changes so it's just going to stop and report an error. If iTunes launches slower or an event during the replay takes longer to perform due to different background processes running, it's going to have the same affect.

Enabling automatic downloads in iTunes and using Automator to enable your network device at a designated time might be a better solution.

Personally haven't tested this myself with iTunes but did with having automatic updates enabled in the App Store.

First get your interfaces device name from System Report.

Then create a shell script event in Automator:

networksetup -setairportpower en1 on

Change "en1" to the device name in System Information on your computer. Since you're on a MacBook Air your wifi adapter is most likely en0.