Registry changes?

I'm trying to get some code to work with Windows 7 64-bit. It's a part where a registry value should be removed after cloning.
The opening of the registry key is done with success but I recieve the error that the file is not found (though the value is there) when trying to delete the value.

Code:

int remove_susid(void) {

    int rst;
    HKEY rkey;

    print_log(0, "Remove SUS Client ID...");
    rst = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
	    "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\WindowsUpdate", 0, KEY_SET_VALUE, &rkey);
    rst = RegDeleteValueA(rkey, "SusClientId");
    print_log(1, "%s\n", !rst ? "Ok" : "Failed");
    RegCloseKey(rkey);

    if (rst)
	print_log(0, error_msg(rst));

    return rst;

}

In an other part of the code some registry values should be changed.

Code:

    rst = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
	    "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon", 0, KEY_SET_VALUE, &rkey);
    rst |= RegSetValueEx(rkey, "DefaultDomainName", 0, REG_SZ, "xxxx", 5);
    rst |= RegSetValueEx(rkey, "DefaultUserName", 0, REG_SZ, "Administrator", 14);
    rst |= RegSetValueEx(rkey, "AutoAdminLogon", 0, REG_SZ, "0", 2);
    RegCloseKey(rkey);
    print_log(1, "%s\n", !rst ? "Ok" : "Failed");

All calls succeeds but nothing gets done.

All run with administrator access...

I'm pretty sure it worked on a Windows 7 32-bit computer. Have I missed something?

Are you sure it's not actually buried in the wow6432node key? The 64-bit windows registry is a peculiar thing.

Wonderful...

Thank you very much.