AGP Rate 0x: what means that?

[Pinguin]

I've installed on my PC (PIII 600 5 years old) a Nvidia TNT2 graphics card.
O.S. is Linux Ubuntu Breezy 5.10 Kernel 2.6.12-10-686.
I've installed nvidia "legacy" drivers corresponding at 1.0-7174 nvidia driver.
The command
cat /proc/driver/nvidia/agp/status
reports this:
Status: Enabled
Driver: AGPGART
AGP Rate: 0x
Fast Writes: Disabled
SBA: Disabled

What means AGP Rate: 0x?
My motherboard and BIOS support AGP up to 2x.
Is there something wrong on my system?
Must I configure some settings to have AGP rate work at 2x?
Thank you.
Here is the report of nvidia-bug-report.sh.

[Dazz]

It means that you don't have the correct AGP motherboard drivers installed to take advanatge of AGP and will be working in PCI compatibility mode i highly recommend you upgrade the motherboard drivers.

[DrFishstik]

Try using nvagp

Here are instructions, they are for the 80 series of drivers but will work the same for the 71 series

http://download.nvidia.com/XFree86/Linux-x86/1.0-8178/README/appendix-f.html