Input method editor keyboard shortcut (CTRL+SHIFT+0) switches the input language in Vista
An input method editor (IME) keyboard shortcut lets you switch the input language. By design, the CTRL+SHIFT+0 key assignment is standard for all users. However, some applications might use this keyboard shortcut for other purposes. In this case, the application will not work as expected when you use the shortcut with the application.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB967893.