Bug with admin_gatekeeper() in Administration

Hello Guys,

I've got this Issue. Tried on two different webspace, but no chance, dont know how to fix that.

Fatal error: Call to undefined function admin_gatekeeper() in /home/www/web311/html/book/mod/tidypics/pages/admin.php on line 6

1) I uploaded tidypics in mod
2) activated it
3) It seems to run normally, but If I go to administration
4) click on tidypics administration, see the Settings tab
5) but if I try to switch to any other tab, i've got this Issue above.

Found same Issue in that Group, without Solution:

Used Google for hours. Please help.