I have noticed that the vast majority of computers have started failing both BIOS and hardware inventory tasks.  This seems to have coincided with upgrading to 7.0.7270.

The agent log of one of the failing machines looks like:

<event date='Mar 15 13:30:13' severity='4' hostName='PC044' source='Client Task Agent' module='client task agent.dll' process='aexnsagent.exe' pid='812' thread='4552' tickCount='1212853796' >
  <![CDATA[Task: BIOS Inventory Task has started]]></event>

<event date='Mar 15 13:30:13' severity='4' hostName='PC044' source='Client Task Agent' module='client task agent.dll' process='aexnsagent.exe' pid='812' thread='4552' tickCount='1212853796' >
  <![CDATA[Task: BIOS Inventory Task has finished]]></event>

<event date='Mar 15 14:01:38' severity='4' hostName='PC044' source='Client Task Agent' module='client task agent.dll' process='aexnsagent.exe' pid='812' thread='4556' tickCount='1214737953' >
  <![CDATA[CTaskExecutionEngineBase::OnProcessInstanceRequest(): Processing request Stop for 54bd0ba1-68ab-4cf0-8b08-680ba68e1fd6]]></event>

<event date='Mar 15 14:01:38' severity='4' hostName='PC044' source='Client Task Agent' module='client task agent.dll' process='aexnsagent.exe' pid='812' thread='4556' tickCount='1214737953' >
  <![CDATA[CTaskExecutionEngineBase::OnProcessInstanceRequest(): Processing Stop]]></event>

<event date='Mar 15 14:01:38' severity='4' hostName='PC044' source='Client Task Agent' module='client task agent.dll' process='aexnsagent.exe' pid='812' thread='4556' tickCount='1214737953' >
  <![CDATA[CTaskExecutionEngineBase::OnProcessInstanceRequest(): 54bd0ba1-68ab-4cf0-8b08-680ba68e1fd6 not found in any list]]></event>

Any ideas?