To load the GMK you are going to need the GMXML extension. This can be found below.
To fix the "Failed to extract the GMK file" error, you need to either install the JDK (Java Development Kit) or have a System Variable pointing to it.
Link for the JDK: http://www.oracle.co...oads/index.html
To set up a variable.
Right click on Computer/My Computer in the start menu and select properties.
Click Advanced System Settings
In the Window that opens, goto the Advanced tab
Click the Environment Variables
Under System Variables find one called "path" (If its not there create it)
Set the variable as the directory of you JDK setup. For example for me its "C:\Program Files (x86)\Java\jdk1.6.0_23\bin"
If there is already something in the variable add a semi colon. For example "C:\Windows\SysWOW64;C:\Program Files (x86)\Java\jdk1.6.0_23\bin"