Read Instructions Carefully
This is a kext for all Realtek 82xx Ethernet chips.
I have test it on a RTL8211BL and MCP73, but it works on all 82xx and nforce chips
Only for 10.8, but you can test it on other 10.7.x and tell me if it work
I mean 82xx not 81xx
for 64-bit and 32-bit