Cannot get a successful backup

We use Azure for our back office.  We have a domain controller on an Azure virtual network that also serves as our file server.  While attempting to do a full backup, the backup service runs "Estimating size of backup items..." and then errors out with either a "Job Failed" or "Engine encountered an unexpected error.  Please look at the event logs for details"  (event log details below).

I am attempting to backup approximately 175GB of data.  I am running successful backups from other servers (10GB) and I can back up locations under 1GB on the DC.

The event log entry:

Log Name:      Application
Source:        Application Error
Date:          4/17/2014 11:03:38 AM
Event ID:      1000
Task Category: (100)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      server-name.domain.local
Description:
Faulting application name: cbengine.exe, version: 1.0.8236.0, time stamp: 0x52442be2
Faulting module name: KERNELBASE.dll, version: 6.2.9200.16857, time stamp: 0x530e784b
Exception code: 0x809909c2
Fault offset: 0x0000000000047b8c
Faulting process id: 0x7774
Faulting application start time: 0x01cf59e91fc4eca4
Faulting application path: C:\Program Files\Windows Azure Backup Agent\bin\cbengine.exe
Faulting module path: C:\Windows\system32\KERNELBASE.dll
Report Id: 7436e9cb-c641-11e3-942e-00155d476158
Faulting package full name:
Faulting package-relative application ID:
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Application Error" />
    <EventID Qualifiers="0">1000</EventID>
    <Level>2</Level>
    <Task>100</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2014-04-17T15:03:38.000000000Z" />
    <EventRecordID>162093</EventRecordID>
    <Channel>Application</Channel>
    <Computer>server-name.domain.local</Computer>
    <Security />
  </System>
  <EventData>
    <Data>cbengine.exe</Data>
    <Data>1.0.8236.0</Data>
    <Data>52442be2</Data>
    <Data>KERNELBASE.dll</Data>
    <Data>6.2.9200.16857</Data>
    <Data>530e784b</Data>
    <Data>809909c2</Data>
    <Data>0000000000047b8c</Data>
    <Data>7774</Data>
    <Data>01cf59e91fc4eca4</Data>
    <Data>C:\Program Files\Windows Azure Backup Agent\bin\cbengine.exe</Data>
    <Data>C:\Windows\system32\KERNELBASE.dll</Data>
    <Data>7436e9cb-c641-11e3-942e-00155d476158</Data>
    <Data>
    </Data>
    <Data>
    </Data>
  </EventData>
</Event>