bhay3s
If you had done a search of these forums on Realtek R8169 you would have found many answers.
I suggest you do a search, link is at top of forums.
They seem to say it will not work on sme 7.5.1 based on Centos 4 but may work using the other driver mentioned.
They also say it will work on sme8 based on Centos 5
It's not the fault of or a bug in sme, it's just due to whether support exists for that chipset in the kernel. The newer kernel in Centos5 supports it, therefore it works in sme8b7