Visual studio 2010 doesn't recognize prefabs

Because mono develop won’t open, I am using Visual studio 2010 (not express), I open the solution that contains my unity scripts and try to instantiate a new game object from a prefab, but it claims that BlockFab (the prefab) does not exist in the current context, so I cannot run the code. I have used this method the same exact way with mono develop, and it worked before, but here it does not.

The line of code:

Instantiate(BlockFab, new Vector3(0.3f, 17.7f, -48.9f), Quaternion.identity);

Any help would be extremely appreciated!

What is type of BlockFab variable? If this is name of prefab you should load it before with Resources.Load() method.

Extremely sorry for delayed response (Its finals time), but it turns out I pulled a stupid. In the previous use of the Instantiate method I mentioned, the prefab was made an public attribute and assigned to using the unity editor. Sorry again for that.