Why am I unable to Tether using ClockworkMod Tether?

[AC Question]

Unable to Tether using ClockworkMod Tether

I keep getting this message:

Checking phone status...
a16db97e Connecting to device.
a16db97e Checking if package is installed.
Error listing pacakges. Assuming Tether.apk is already installed.
a16db97e Setting up adb port forwarding to port 30002.
a16db97e adb port forwarding results:
{ '0':
{ [Error: Command failed: error: device offline
] killed: false, code: 1, signal: null },
'1': '',
'2': 'error: device offline\r\n' }
a16db97e Error forwarding:
{ [Error: Command failed: error: device offline
] killed: false, code: 1, signal: null }

I have Windows 7 and a Samsung Galaxy S3. Has anyone else also received this error?