Construction Liens

I'm a GC, a sub worked on a project for me, he never told me the backhoe he was using was rented. He has been done for nearly 3 months now. I just got a call from the rental company informing that if they're not paid in full ($5k) they'll take a lien on the property, I certainly don't want that to happen as I'm still working on the project.This sub was looking for an advance from me and told me he has a case being settled anytime now (I have the attorney info). How long does a subcontractor or vendor have to put a proper lien on a property and do I have to pay them. The sub will not return any calls from me or them ... what do I do?

In order to have protection from liens on a remodeling job, does the property owner need both the sworn Contractor's Final Affidavit from the general contractor AND lien waivers from the subs or will the Contractor's Affidavit suffice?

The Owner pays the contractor. The contractor pays the sub contractor, Gets a wavier from the sub. The sub contractor does not pay the material man who has a NTO. The Material man files a lien, who has to pay this lien off? The owner or the contractor who has paid the the Subcontractor in full?

Can you be charged criminally as a contractor if you have been paid in full on a contract and the subs haven't been paid and leins are being filed?

My husband and I built a home in Minn last year. closed on our house May 7 2010. after we moved in we received 3 mechanics lien notices - these are all filed with the county we live in. We paid for our home - the builder walked away with around 7K of our money plus he did not pay the subs. as home buyers do we have any protection? and can we get these liens removed? I appreciate your help! One other point - our builder went out of business and skipped town.