Cannot Open DataExplorer Tab (dbml) in VS2008

Suddenly my VS2008 could not open the DataBase Tab explorer.
It's kind a strange error...but after some searching at 'om Google',
i found this steps:

1. open Visual Studio Command Prompt from Visual Studio start menu
2. run this syntax on it:

• devenv /setup
• devenv /resetskippkgs

*this does solve the problem :D
**continued to the code...

ps: was taken from http://forums.asp.net/p/1128278/1781357.aspx#1781357