Please write bug reports in English.

Sorry :-)
If you delete your answers and clear the survey you can't restart it with a page reload - you gotta load the page through the URL.
Also the process bar is still visible after clearing the survey, maybe a template issue.
If you have cleared the survey there is no button to restart it, so users usually press F5 where a "session expired" appears.
So you can't do a reload or F5, you need to go to the adress bar and load the URL again (or reclick the original link).
reproducable: leave survey and clear results, then press F5

Could you please attach a short test survey?

Also, feel free to be more precise in your "How to reproduce" description, something like:

1. Activate survey
2. Execute survey
3. Fill in one answer
4. Click Clear
5. Click F5

etc...

just to be sure I created a new one, so it isn't something from older migrated surveys - it's the same with a new blank survey.
Steps:
1 execute survey OR open link directly
2 clear (no answer filling needed)
3 F5
result: We are sorry but your session has expired. Either you have been inactive for too long, you have cookies disabled for your browser, or there were problems with your connection.

Awesome, will try.

Missing confirm page.

Selection_376.png (14,062 bytes)   

Selection_376.png (14,062 bytes)   

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=25872

I'll consider this solved. F5 still gives error, but that's intended (more or less). Instead, the link "Restart survey" should be used in the confirm page.

Fix will be included in next release (3.0.2).