After several unsuccessful attempts at getting support from Google to figure out why EchoSign does not allow me to type my signature or sign and hit accept I decided to ask here. A valid google apps domain is needed to test this. To get to the agreement follow the steps at this URL. HIPAA Compliance with Google Apps - Google Apps Administrator Help Attempt to sign it does not allow you to "Apply" your signature. I've tried every browser and a computer with Adobe Acrobat as well for good measure.
I'm having the exact same issue, glad I'm not the only one.
I have figured out a workaround. Although it still won't let me type anything in the box, I found that once I created an actual Google+ profile, it filled in the name I used in the profile. Just make your name whatever you want in the signature box, and then when you are done, delete the name or the profile entirely.
Hope that helps.