Trouble Rendering Mesh

Hello--

I'm trying to implement the script located here but running into problems. I'm using the C# version of the script here: http://pastebin.com/KffepxzJ

Basically, everything seems to run fine but I get a pink square where the mouse cursor is. The expected behavior should be a rendered mesh grid that follows the contour of the terrain.

Here's my build so you can see what it's doing: http://54.200.152.65/builds.html

Any help is appreciated!