He is pointing out that another twitter user is harassing his girlfriend.

https://twitter.com/#!/alecbaldwin/status/182315229529636864

https://twitter.com/#!/alecbaldwin/status/182315430243860480

https://twitter.com/#!/alecbaldwin/status/182315832867696640

https://twitter.com/#!/alecbaldwin/status/182316088632152065

We didn’t include the tweet by Baldwin naming the person he says is harassing him.  Last tweet from Baldwin:

https://twitter.com/#!/alecbaldwin/status/182322866338017282