That error can mean a lot of things - primarily certificate issues or group policy issues (which may be beyond the scope of this forum, depending). Here's a Bing on the error number: http://www.bing.com/search?q=0x8007003A&form=MSDTLB.
Please explain the problem itself in more detail. What version of Vista are you using (name, version, SP, bit size)? What is the make and model and number of the NAS server? What happens when you try to copy the files? Does the error occur in the other direction as well (from the NAS server to the laptop)? What is the EXACT error message (not just the number)? Have you ever been able to copy between the laptop and the NAS server or is this the first attempt? If you did it before, what has changed since then (hardware or software)? How long have you had this problem? Have you contacted the NAS technical support people for assistance and what did they say?
We need more information in order to help you. We await your response - along with any other details you can provide which might be of assistance (not just those requested).
Good luck!
Lorien - MCSE/MCSA/Network+/A+ --- If this post helps to resolve your issue, please click the "Mark as Answer" or "Helpful" button at the top of this message. By marking a post as Answered, or Helpful you help others find the answer faster.