Microsoft Office Word 2007 Mail Merge - Labels Only printing top line and bottom

Download the MergeLabelFix add-in from the following page of my One Drive:
http://bit.ly/1hduSCB 
The file needs to be saved in the Word Startup folder.  In Windows XP the default location for that folder is

C:\Documents and Settings\[User Name]\Application Data\Microsoft\Word\STARTUP

In Windows Vista and Windows 7, 8 or 8.1 it is

C:\Users\[User Name]\AppData\Roaming\Microsoft\Word\STARTUP

If you do not see the AppData folder: -

In Windows 7, - In Windows Explorer, click on the Organize drop down and then on Folder and search options and in the Folder Options dialog, go to the View tab and select the item "Show hidden files, folders, and drives".  While there, it is a good idea to uncheck the box of "Hide extensions for known file types".

In Windows 8 and 8.1, in the File Explorer, click on Options on the View tab of the ribbon and then on the View tab in the dialog that appears and select the item "Show hidden files, folders, and drives".  While there, it is a good idea to uncheck the box of "Hide extensions for known file types".

Re-start Word after saving the add-in in the Startup Folder.

The add-in contains code that will overcome the issue that you have