Help...Mac loosing connection with AP One

My client is using all Mac products and keeps loosing connection. On my Dell I have no issues. I am showing full signal strength on my Laptop and have not lost signal. His furthest macbook is 40-45 feet from the AP. In line of sight is 2 sheetrock walls. Their are no ducts in the walls or any heavy electrical loads. No mirrors or glass. AP is set to channel 6, WPA2. I Changed channels and issue still exists. :confused:
Any Thoughts?

I would first make sure he is running on the latest firmware, it can be downloaded from our website:

If the issue still persists, you can start a support ticket via this link: