It took you two days to figure this out? ... You might want to read this:

http://answers.unity3d.com/questions/5507/what-are-the-syntax-differences-in-c-and-javascript

It should clear up a lot of confusion you might have.

As for your code, C# won't implicitly cast from Component to your own class, ObjectInfo. You need to explicitly cast it, and personally, my favorite way is with the as keyword. You also need to specify the type with GetComponent() (because GetComponent()'s parameter is a Type, so you need to use typeof()), although there are other ways of using GetComponent(), this is my favorite way).

tmpTexture = (GLOBALZ.objectsInWeapons[(4 * rows) + colmn].GetComponent(typeof(ObjectInfo)) as ObjectInfo).iconTexture;

Although that is an extraordinarily ugly line of code. I would make it neater:

GameObject tmpObject = GLOBALZ.objectsInWeapons[(4 * rows) + colmn];
ObjectInfo tmpInfo = tmpObject.GetComponent(typeof(ObjectInfo)) as ObjectInfo;

if(tmpInfo == null)
{
     // Couldn't retrieve the "ObjectInfo" script here.
}
else
{
     tmpTexture = tmpInfo.iconTexture;
}   

See? Much, much easier to read and understand. :)