Ubuntu
Versión 12.04 (precise) de 64-bit
Núcleo Linux 3.8.0-33-generic
GNOME 3.4.2
Mermory: 7,8 GiB
Processor: Intel® Core™ i7-3770 CPU @ 3.40GHz × 8

renderer: 'GeForce GTX 650 Ti/PCIe/SSE2'
vendor: 'NVIDIA Corporation'
version: '4.2.0 NVIDIA 304.88'

Blender Version

version 2.69 (sub 2), revision b'61181'. b'Release'
build date: b'2013-11-07', b'02:02:33'
platform: b'Linux:64bit'

Short description of error

After coping an object having a Mesh_Cache modifier, the message of "Copy to z-buffer" shows, when you paste the object to other scene or file the path into the Mesh_Modifier changes adding some "../" at the beggining of the original file, making the object lost the Cache.

I had include a Zip file whith a screencapture and the files used to reproduce the issue.

Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps

• Create a new blend file
• Animate an object
• Select the object
• Export animation as MDD
• Create other new file with the same (new) object than previous file
• Add the mesh_cache modifier and link to the exported cache
• Save the file, just to be sure all will be at the same path
• Create a new empty Blend file and save it
• Copy the object with the mesh_cache modifier from the previous saved file to the empty file
• Go to modifier section of the object and you will find it losses the correct path to the cache, although the directory structure is at the same levels

Best regards