Internet problem with VT6102 [Rhine-II]

Hi there!
I have a very strange problem!
I have a **A7V8X-X motherboard with VT6102 [Rhine-II] **on board network device.
Internet connections work fine for long time on openSuse 10.3, 11.1 11.2 and 11.3.
But since a few weeks ago, internet connections began to fail: several times when I want to open any Internet site with Firefox, it answers:

"Problem loading page"

"Unable to connect"
"Firefox can't establish a connection to the server at forums.opensuse.org."

but, by clicking “Reload current page” button, some times the page is loaded normally.

Also, the “Updater Applet” has the same problem to connect to Internet, with the message:

PackageKit Error repo-not-available: Failed to download /repodata/repomd.xml from http://download.opensuse.org/update/11.3/

but if I insist a couple of times, the connection is successful.

I reject the possibility of a hardware problem because with Windows XP the Internet connections work fine.

The problem is still stranger because I loaded a Ubuntu Live CD, and I have the same problem.
I leave some data of my network settings (, but same settings work fine a month ago):

ASIA:~ # ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0C:6E:20:E5:8C  
          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:6eff:fe20:e58c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10438 errors:0 dropped:0 overruns:0 frame:0
          TX packets:9219 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:11366537 (10.8 Mb)  TX bytes:1277932 (1.2 Mb)
          Interrupt:23 Base address:0xc000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:268 errors:0 dropped:0 overruns:0 frame:0
          TX packets:268 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:26927 (26.2 Kb)  TX bytes:26927 (26.2 Kb)

ASIA:~ # route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     *               255.255.255.0   U     0      0        0 eth0
link-local      *               255.255.0.0     U     0      0        0 eth0
loopback        *               255.0.0.0       U     0      0        0 lo
default         192.168.1.1     0.0.0.0         UG    0      0        0 eth0

Do you have any idea?

What happens if you disable ipv6?
that chould explain why XP does not have the problem…

With ipv6 enabled or ipv6 disabled, I have the same problem!

Thank you for ask.