Here is the dsdt_fixed.txt file I edited with the HDMI Audio code. 1 interesting point is that I found a topic where someone added this under Device (PGEP) and another where it was under Device (PCI0) so I'm not sure which one to do. Not that I can get it to compile anyway. Here's where I think the error might be.
./dsdt_fixed.txt 8342: Store (And (Arg1, 0xFFFF), _T_1)
Error 4063 - Object does not exist ^ (_T_1)
ASL Input: ./dsdt_fixed.txt - 14195 lines, 467142 bytes, 6288 keywords
Compilation complete. 1 Errors, 7 Warnings, 1 Remarks, 78 Optimizations