Ok. The object in your scene is wrong scaled, but if reload the fence from the library (using the same units) it is loaded correctly. This seems a problem specific to your configuration, but not sure what.
Please, do the following test:
1) Reset Max. Load the scene C:\Program Files (x86)\Itoo Software\RailClone Pro\lib\default1\Architecture\Fences\Vynil\fencing_vynil1.max. If the Units are different, select Adopt the File's Unit Scale.
2) What is the size of the picket fence (_RC_fencing_vynil_4) ?
3) Does it change repeating the process but selecting Rescale the file Objects to the System Unit Scale ?
4) Reset Max and merge all objects of the above scene. What is the result ?
5) Send us the file 3dsmax.ini stored at C:\Users\<your username>\AppData\Local\Autodesk\3dsMaxDesign\2013 - 64bit\ENU
One more question: what Max update have you installed, PU6 ?