I have a MacBook Air OS X 10.7.4 and Adobe 10.1.4, but cannot open simple PDF files sent to me
I've moved your question to the Adobe Reader forum which is the appropriate location.
You can open most pdf files using the Preview application. You should be able to use Reader 10.1.4 you installed. What happens when you try to open them. Please tell us how they are sent to you and the exact process you are using to open them.