On my productive system (see specs below) I got an SQL-error after an attempt to login:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1:SELECT define_questions, edit_survey_property, delete_survey FROM lime_surveys_rights WHERE sid=1984839014933 AND uid =

I don't know why the uid is empty and this thread:
http://www.limesurvey.org/support/forums/9-german-forum/27747-sql-anmeldefehler
recommends to set session.save_dir properly and to disable Suhosin, but my session.save_dir has 777 permissions.
Disabling Suhosin oviously can't be a good solution (especially since I think that it is disabled anyways on my server).

I figured that admin/database.php line 68 causes this problem, because the SQL-statement doesn't have good error-handling. If uid is a string, you have to encapsulate uid in apostrophes. Otherwise, you have to make sure that it is 0, when it is treated as an int (and not empty).

Possible Solution:
Line 68: $actsurquery = "SELECT define_questions, edit_survey_property, delete_survey FROM {$dbprefix}surveys_rights WHERE sid=$surveyid AND uid = ".$_SESSION['loginID']; //Getting rights for this survey

Fix: $actsurquery = "SELECT define_questions, edit_survey_property, delete_survey FROM {$dbprefix}surveys_rights WHERE sid=$surveyid AND uid = '".$_SESSION['loginID']."'"; //Getting rights for this survey

Obviously, you should check if this is an appropriate solution, since I have no clue how uid is obtained, but it seems to work for me.