I do not see this file in my folders and might be causing you problem.
viral_outbreak\grendel_destroy.fpi
I know that there is a shader variable called on these models. So with out a lot of leg work trying to trace it down, I am out of answers.
Have you checked this thread for a possible solution?
http://forum.thegamecreators.com/?m=forum_view&t=195717&b=21
There are fixes for this model and two others from Flatlander.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 4gb RAM, Nvidia gtx660, Windows 7 Pro 64bit