Auto body repair & detailing: 64 Ford Falcon, ford falcon, retirement dream

Question
Hoping you can really help me. I have a 64 Ford Falcon. I took it into a shop to have the door panels staightened. They put the car on blocks and told me the car bowed in the middle and that something was wrong with the frame. Unfortuneately the person who had the car before me sprayed car bed lining on the under carraige of the car and I have no idea what could be wrong. Would you have any idea, how this can be fixed, is this serious, etc. I am worried that the car may be unsafe. Other than this the car is very sound and I just spent 12K on a new engine so I am completely devastated, this was my retirement dream.

Answer
tux
  if the doors don't fit and close properly a reason could be that the car was supported wrong during repairs .  jacking up a uniboby car in the wrong place   [center of rocker panel]  could bow/bend the structure  think see-saw leaving perminent  structural damage and will require a "frame" straightening to remove a reverse sag condition

bill