Nothing is different with your system. It's due to certain security rules Microsoft introduced in kernel where they don't allow direct access to PCIe configuration space on some systems anymore.
Since this restriction resulted in BSODs on some systems, we have globally disabled the "Low-level PCI Access" option for all systems including legacy ones. But I didn't realize that the alternate function (via HAL) doesn't work as expected on XP and here the direct access is still required on systems like yours (where we need access to extended PCIe space). This will be fixed in the next HWiNFO build by enabling this option by default on such systems.