It happens to both newbie hubbers and oldies as well. I have been through this 'unproductive phase' a lot many times during my freelance writing career, while blogging for my own blog and now since I joined HubPages a week back.
I follow different methods to deal with each of these 3 different situations.
1) In my freelancing, I just remind myself about the deadline of the project promised to the client and the perils of sending in late work (there is a risk of not getting paid for all the hard work if it is turned in late, and sometimes the client pays but leaves negative feedback that can mar your reputation as a freelancer)
2) When I am procastinating on my blog, I remind myself of the expectations that my regular readers have of me and it pushes me to start writing.
3) As for HubPages, I keep reminding myself how badly I want to see my score shining at 100 and I start writing.