Discussion forum is not working well after restoring the site collection.

I have created a new site collection of type community site on my development machine, then I have backup the site collection and I restore it inside staging server server.

I am lo-gin as the site collection administrator on the  staging environment and I am able to add new discussion , new category. but if I try to click on the discussion to read it or to reply to it I will get the following error:-

404 NOT FOUND

And the URL generated will look as follow:-

http://gvstg01:40708/discussionforum/generalDiscussion/SitePages/Topic.aspx?RootFolder=%2Fdiscussionforum%2FgeneralDiscussion%2FLists%2FCommunity%20Discussion%2Fw&FolderCTID=0x0120020099E78C8B0924BC4E979E17218349CC35&SiteMapTitle=General&SiteMapUrl=http%3A%2F%2Fgvstg01%3A40708%2Fdiscussionforum%2FgeneralDiscussion%2FSitePages%2FCategory.aspx%3FCategoryID%3D1%26SiteMapTitle%3DGeneral.

Can anyone advice what might be causing this??, baring in mind that the discussion forum is working well on development machine. the problem is occurring on the staging environment , where I have restore the backup site collection.

Thanks in advance for any help.