I have a similar error report from my customer. (I am a Japanese reseller)
When loading Meadows of Presets, get the error "3d_vray.mat dosen't exist".
Does that file (3d_vray.mat) exist on the corresponding location (C:\Users\<yourUsername>\AppData\Local\Itoo Software\Forest Pack Pro\matlib)?
I would suggest reinstall the problematic packages in the following way from the Update Manager:
If you cannot see installed packages, Go to the View menu and select Installed Packages.
Click on the (i) icon for the package you'd like to remove
From the Details Dialog, click Uninstall.
After it is uninstalled, hit the Install button on the bottom of the Update Manager.
Hope that helps.