You'll need to tell us a bit more about what you are trying to do. That's a
very non-descript general error.

But to handle the obvious ones. Are you trying to open a full SharePoint 2010
site? SharePoint Designer can't open individual pages or non-SharePoint sites
like previous versions of the product. It also can't open Sharepoint 2007
sites.

OK here is a brief story about my build.
I have 2 servers:
Server 1 --> is WIN08 R2 Enterprise with SQL08 R2 Enterprise.
Server 2 --> is WIN08 R2 Enterprise with MSS 2010 and SharePoint Designer 2010 .

I have installed these tow servers from scratch and without any problems or
error at all, and installing SharePoint 2010 Installation is done and configured
also.
Then, I created 2 Web Apps one as a Publishing Portal and the other as Team
Site.

And whenever i am trying to open the any of these sites it's giving me this
error.
What i Figure out is the connection to any of these sites it's stop in this
stage:
(Opening Site: http://server4:8080/sites/RCEP_Test...)
Commnicating with Web Service...

and then the pop window is coming:
The Server could not complete your request.
For more spacific information, click the details button.

and also this is from the event log:

WebHost failed to process a request.
Sender Information:
System.ServiceModel.ServiceHostingEnvironment+HostingManager/66502754
Exception: System.ServiceModel.ServiceActivationException: The service
'/_vti_bin/client.svc' cannot be activated due to an exception during
compilation. The exception message is: Access is denied.
. ---> System.Runtime.InteropServices.COMException (0x80070005): Access is
denied.

at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
at System.DirectoryServices.DirectoryEntry.Bind()
at System.DirectoryServices.DirectoryEntry.get_AdsObject()
at System.DirectoryServices.PropertyValueCollection.PopulateList()
at System.DirectoryServices.PropertyValueCollection..ctor(DirectoryEntry
entry, String propertyName)
at System.DirectoryServices.PropertyCollection.get_Item(String propertyName)
at
Microsoft.SharePoint.Client.ClientRequestServiceBehaviorAttribute.<>c__DisplayCl\
ass1.<get_AuthInfo>b__0()

at
Microsoft.Office.Server.Security.SecurityContext.RunAsProcess(CodeToRunElevated
secureCode)
at
Microsoft.SharePoint.Client.ClientRequestServiceBehaviorAttribute.get_AuthInfo()
at
Microsoft.SharePoint.Client.ClientRequestServiceBehaviorAttribute.GetAllAuthenti\
cationSchemes(AuthenticationSchemes&
defaultOne)
at Microsoft.SharePoint.Client.Services.EndpointCreator.AddEndpoints()
at
Microsoft.SharePoint.Client.Services.MultipleBaseAddressWebServiceHost.OnOpening\
()

at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at
System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(Str\
ing
normalizedVirtualPath)
at
System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvaila\
ble(String
normalizedVirtualPath)
--- End of inner exception stack trace ---
at
System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvaila\
ble(String
normalizedVirtualPath)
at
System.ServiceModel.ServiceHostingEnvironment.EnsureServiceAvailableFast(String
relativeVirtualPath)
Process Name: w3wp
Process ID: 4856

Take a look at the following article. If you are trying to open the sites from
the server you need to apply one of the fixes for the Disable LoopBack problem.

www.harbar.net/.../disableloopbackcheck-amp-sharepoint-wha\
t-every-admin-and-developer-should-know.aspx

Looking at the error log the other problem might be that you don't have
permissions on the site you are trying to open. Can you browse to pages on that
site in IE?

i have yes one point here about browsing the site.
when i am trying to browse the site from the server itself the site is coming
but without any images, but if i browse the site from my local machine the site
is open fine with all the images.

Note: that the user i am trying to login with is a full admin user for the farm
and is the same user i used when start installing sharepoint 2010.

Being a Farm Admin doesn't automatically give you rights to a regular site
collection. It gives you the right to assign a site collection admin so you can
always give yourself rights. But Farm admins only have rights to central admin
by default.

Check the article on DisableLoopBack check that may be your problem.

The user that I am talking about is not only a farm admin its also admin for the
web apps I am working with.