This is a common error when the version of MR shader (fshader3.dll) doesn't match with the plugin (ForestPackPro.dlo). Please try this:
- Create a empty folder at C:\viztest
- Install Forest 3.02 there, selecting "3DS Max 9 / Viz 2008 (32 bits)".
- Check if these files are the same that the existing at your Viz installation (use file size and date for checking). If not, overwrite them:
C:\viztest\plugins\ForestPackPro.dlo
C:\viztest\mentalray\shaders_autoload\include\FShader3.mi
C:\viztest\mentalray\shaders_autoload\shaders\FShader3.dll
I just installed Forest 3.02 patch on my Viz 2008, and updated it correctly... but may be it failed on your installation.
Please, post here the results, to know if there is some problem with the installer and we must fix it.