Problem while trying to take the back up of my PC

Hi experts,

I have been facing a problem while trying to take the back up of my PC in the house. It contains more data than the available space on the server. While selecting the back up option, it throws an error message indicating that it needs to be done with VSS, but I have no idea regarding VSS. I searched to and fro for this, but found nothing.

Appended below, please find a couple of logs:

———————————

From WHS 2011:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">

<System>

<Provider Name="Windows Server"/>

<EventID Qualifiers="53247">269</EventID>

<Level>2</Level>

<Task>1</Task>

<Keywords>0x80000000000000</Keywords>

<TimeCreated SystemTime="2012-08-07T23:15:12.000000000Z" />

<EventRecordID>2435</EventRecordID>

<Channel>WSSG</Channel>

<Computer>SERVER</Computer>

<Security />

</System>

<EventData>

<Data>Theace</Data>

<Data>6</Data>

</EventData>

</Event>

—————-

<-            From the client computer, Application Log:              ->

Log Name:      Application
Source:        VSS
Date:          2/5/2012 5:05:11 PM
Event ID:      555
Task Category: None
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      Rhns
Description:
Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface.  hr = 0x80070005, Access is denied.
. This is often caused by incorrect security settings in either the writer or requester process.

Operation:
   Gathering Writer Data

Context:
   Writer Class Id: {e8132975-6f93-4464-a53e-1050253ae220}
   Writer Name: System Writer
   Writer Instance ID: {1637d467-3d77-42dc-8c48-854e4d8f04ed}
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="VSS" />
    <EventID Qualifiers="0">8194</EventID>
    <Level>2</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2012-08-08T00:05:11.000000000Z" />
    <EventRecordID>47051</EventRecordID>
    <Channel>Application</Channel>
    <Computer>Theace</Computer>
    <Security />
  </System>
  <EventData>
    <Data>0x80070005, Access is denied.
</Data>
    <Data>

Operation:
   Gathering Writer Data

Context:
   Writer Class Id: {e8132975-6f93-4464-a53e-1050253ae220}
   Writer Name: System Writer
   Writer Instance ID: {1637d467-3d77-42dc-8c48-854e4d8f04ed}</Data>
    <Binary>2D20436F64653A20575254575254494330303030313236302D2043616C6C3A20575254575254494330303030313231342D205049443A202030303030313836382D205449443A202030303030323932302D20434D443A2020433A5C57696E646F77735C737973746 56D33325C737663686F73742E657865202D6B204E6574776F726B53657276696365202020202020202D20557365723A204E616D653A204E5420415554484F524954595C4E4554574F524B20534552564943452C205349443A532D312D352D3230</Binary>
  </EventData>
</Event>

——-

Is there anyone who can guide me to solve this issue? Please help me.

Thanks beforehand.