output file absent???

same problem recently,after computing for several minutes it exit with the error 'output file absent',and repeats again soon to another wu,why?

Guys, this message can mean so much.
The real reason for crashing you only find in the report file. Look into your tasks in your account under result ID, there is the output of the report file.
But I'm guessing it's simply the fact that session 195 needs very much memory, so it should been have errored out because of not getting enough.

http://www.renderfarm.fi/result.php?resultid=535219

Unhandled Exception Detected...

- Unhandled Exception Record -
Reason: Out Of Memory (C++ Exception) (0xe06d7363) at address 0x766AE124

Engaging BOINC Windows Runtime Debugger... 

You seem to be returning work units, though. Only some of them fail. I'm not sure of which of your computers you speak. One of them has this work unit:

http://www.renderfarm.fi/result.php?resultid=467921

<core_client_version>6.4.5</core_client_version>
<![CDATA[
<message>
aborted by user
</message>
]]>

Which would seem to point, as the text says, that you have shut BOINC down or cancelled the task manually. If this isn't the case, then we might have a bug.

http://www.renderfarm.fi/show_host_detail.php?hostid=1058

CPU type AuthenticAMD
Six-Core AMD Opteron(tm) Processor 2427 [AMD64 Family 16 Model 8 Stepping 0]
Number of CPUs 12
Operating System Microsoft Windows Server 2008
Standard x64 Edition, Service Pack 2, (06.00.6002.00)
Memory 16377.45 MB

Unhandled Exception Detected...

- Unhandled Exception Record -
Reason: Out Of Memory (C++ Exception) (0xe06d7363) at address 0x76EDE124

Engaging BOINC Windows Runtime Debugger...

16 giggs of ram, the second page of tasks has LOTS or errors, the ones I looked at seem to be out of memory errors..