Thread:Extension talk:Survey/Survey content not loading

May be, this is the same problem as Extension_talk:Survey from Jan. 14 2015:

Fresh install on existing 1.24.1 MediaWiki, installation and update.php seemed to work fine: No error messages, tables created and available. Setting up new surveys seems to work fine, however when trying to take a survey it doesn't show up: "Take a survey" displays edit-options and one line: "Loading survey..." The survey itself doesn't show up.

tested branches:
 * REL1_23 d6ce533
 * REL1_24 c12985a
 * master 8dcdeac

MediaWiki installation:
 * MediaWiki 	1.24.1
 * PHP 	5.5.10 (cgi-fcgi)
 * MySQL 	5.5.40

Any ideas where to dig in?