Events Stored on Network NAS drive no longer accessible in iMovie '09

The NAS volume name is the same. How do I recreate the alias? Thansk

You have several options for creating an alias:

Drag and drop: Click the item you wish to alias and hold down the mouse button. Then, while holding down the Cmd and Option keys simultaneously, drag the item to where you want the alias to appear, and let go of the mouse button. Instead of moving the original item, this will create an alias at the new location.

Contextual menus: Hold down the Ctrl key, and then click the item you wish to alias. The contextual menu will appear, and one of the choices will be Make Alias. Highlight that option, and then let go of the mouse button. The new alias will appear next to the original.

Keystroke: Select the icon of the item you wish to alias, and then press Cmd-l (the lowercase L). The new alias will appear next to its original.

From the File menu: Click the item once to select it, and then from the File menu, select Make Alias. This also creates a new icon next to the original. For example, if you click a file called Gotham.doc, the icon will darken. Then, after opening the File menu and selecting Make Alias, the alias will be created, with the name "Gotham.doc alias, next to the original.
Once you have created an alias, you can move it to a more convenient location, and then rename it or give it a new icon as you wish.

Regards
Stuart

I'm not sure creating an alias fixes anything. The issue is that iMovie '09 does not let me access the Network Drive I used in '08 (nothing changed). Just shows a Yellow Triangle. After reading some other topics on the Apple Discussion sounds like people are having to create symbolic links... but I have no idea what that means.