Unable to restore site collection between my development & and my staging environment

1. SQL server 2008 r2
2. Windows server 2008 r2 datacenter
3. SharePoint enterprise server 2013

On the staging I have the following :-

1. SQL server 2008 r2
2. Windows server 2008 r2 standard (NOT DATA CENTER as for thr dev machine)
3. SharePoint enterprise server 2013

I did the following to move the site collection from ym development to my staging machines:-

1. on the development server I back-up the site collection using the centeral adminstation, and it generate a file without any extension.
2. Inside my staging environment i create a new web application, then I create a new team site.
3. Inside my staging environment,  I open power shell command and I type the following :-

PS C:\Windows\system32> Restore-spsite -identity http://gvstg01/discussionforum/GeneralDiscussion      -path C:\Users\m\Desktop\GeneralDiscussion –Force

but this will raise the following exception, which I can not understand :-

Restore-spsite : <nativehr>0x80070003</nativehr><nativestack></nativestack>

At line:1 char:1

+ Restore-spsite -identity http://gvstg01/discussionforum/GeneralDiscussion

    ...

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

~~~

    + CategoryInfo         : InvalidData: (Microsoft.Share...dletRestoreSite:

   SPCmdletRestoreSite) [Restore-SPSite], DirectoryNotFoundException

    + FullyQualifiedErrorId : Microsoft.SharePoint.PowerShell.SPCmdletRestoreS

   ite