What part of 'not upload finished workunits', (sorry but we're having too many lost in translations). The process is 2 part:

1) The result files that can be seen in the Transfer tab of the client.
2) The "Ready to Report'' which appear when 1) above has completed successfully. One way or the other, these clear (report to server scheduler) no later then 24 hours after the oldest is completed.

Either 1 or 2, please post the content of the message tab when it gets stuck again so we can read where the client is failing to maintain a working connection with the server. Afternoon stats indicate it's not a wider issue.

Not exactly the requested content of the message tab [there's relevant lines before why the backoff and if the internet is up], so will skip in assuming that your system is the issue [3 others continuing was valuable supplemental]. Set a scheduler item in your system to restart the client at intervals may work around the issue. Visit the manual: http://boincfaq.mundayweb.com/index.php?view=502

Diagnosing in BOINC, you could set additional http log flags. See manual at: http://boinc.berkeley.edu/wiki/Cc_config.xml

Bitfinder Internet Security 2013 decided the work coming in was fine, but
the upload was questionable. Got if set now.
Thanks again.