...any ideas, anyone?

Hi everyone, I apologise for my ignorance if this turns out to be an easy fix, but I'm experiencing two problems with my renders that are really starting to bother me as I begin to select my textures for this project. I've taken a render highlighting the problems:

Firstly I seem to be getting this odd blue tint to some (but not all) of my windows. The windows to the left here are supposed to be totally transparent - I've tried different glass vismats, disabling the blue skybox and using GI instead but to no avail. One crucial thing to note here is that the camera position affects whether a window is blue or not, so I imagine it's a reflection problem I just have no idea how to fix.

The other burning question: what is up with the grass here? Again I'm using a grass vismat with a bump map included. The ground face itself is entirely flat, but it looks like that strange stretching starts and stops between each log to the right.

If anyone has any ideas here I'd be very grateful. I'm new to vray having used sketchup for a while and it looks like an invaluable tool, if only i could find my way around it