Please excuse the condescending tone, but you did ask for my approach. So here it is, in the raw:
Firstly, you need to change your attitude. As a successful project manager, you do get along with your team. A PjM who cannot get along with everybody is doomed to failure. If you can't do that - or at least fake it - then get yourself another job.
Secondly, you need to start taking responsibility. Communication is a 2-way street, but if they aren't listening to you, assume the problem is with your approach, attitude or ignorance. Stop blaming other people.
Next: Treat your team with the respect they deserve. Since they are older and senior to you, treat them as such. Possibilities: Ask them for suggestions instead of dictating to them. Maybe the reason they are not cooperating is because they know, from experience, that this project is already dead, for example. I know that respect is old fashioned but it works - especially with people older than you.
Build the team. You may be the PjM but you are useless without your team. Build the team; get to know them. Shmooze to them, find out their background and experience. Find out their favorite drink and pastime and join them. Once you're all good buddies then they will automatically be cooperative.
Keep in mind that as things stand, you are the new bull in a China shop who plans on rocking the boat and creating unnecessary work. They've probably dealt with a dozen of your predecessors and are well experienced in how to get rid of you.
Summary: Stop working for a few weeks and concentrate on creating the team. Hang out with the boys and become their buddy. Then you can start asking their opinion about how to get some work done.