Can't open most Adobe Docs.

I had to get a second computer for my business. It operates on Vista. ~Don't know if that is my problem. Almost every email I get with an Adobe Doc says that attachment was not correctly decoding. How do I fix this? I try opening with other applications and get same error.

My other computer is a mac and I have never had this problem. It is very frustrating to conduct a business and to have to work between 2 computers to open docs.