Can you set debug mode to 2 in application/config/config.php and see if you get a more detailed error message?

Thank you for the debug-hint. Following your response I see that the following statement is executed; it's the "WHERE" line that is wrong. Executing the statement without that line runs smoothly!

SELECT *
FROM lime_survey_712485
LEFT JOIN lime_tokens_712485 ON lime_tokens_712485.token=lime_survey_712485.token
LEFT JOIN lime_survey_712485_timings survey_timings ON lime_survey_712485.id = survey_timings.id
WHERE return
ORDER BY lime_survey_712485.id LIMIT 1

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=10193

Wow, you are really fast. I've corrected that, and is looks good, but:

Another problem occures when I set an offset, in my case, I'll start with record four. The correct syntax would be "LIMIT 4" instead of "OFFSET 4"

=======
SELECT *
FROM lime_survey_712485
LEFT JOIN lime_tokens_712485 ON lime_tokens_712485.token=lime_survey_712485.token
LEFT JOIN lime_survey_712485_timings survey_timings ON lime_survey_712485.id = survey_timings.id ORDER BY lime_survey_712485.id OFFSET 4;

=======
Some notes/questions:

When I try to limit the result to one line, that second parameter will be completely ignored in the SQL-Statement, but that might be handled within code, too. I can't see a handling in the completion state within the SQL statement.

Is there a way to load exactly a specific token's result, too?

if you want to start with record 4 then OFFSET 4 is the right statement?

Fix committed to 2.1 branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=10212