Unable to create 64-bit guest OS with AMD Quad-Core Opteron

Hi,

I am using VMware 1.0.10 on my system that is running RHEL 5.4 x86_64 and has the AMD Opteron 2354 (Quad-Core) AMD chip that shows to support 64 bit OS and also shown to support AMD-V Virtualization.

http://products.amd.com/en-US/OpteronCPUDetail.aspx?id=415 

But somehow when I try to create a 64 bit guest OS, it shows that:

"64-bit guest operating systems are not supported by this host and will not run."

I am not sure why this processor is not supported because clearly the AMD page shows Virtualization is supported.

Thanks in advance.