Problem | Galaxy s2(I9100) - i cant edit anything in my phone(cant even delete an app)

[shayms8]

Hi .

i have a Galaxy s2(I9100), 2.3.6 Gingerbread -
and i have a realy annoying problem !
I cant edit anything in my phone(Move apps from one screen to another \ Delete some apps)

Usually , when i press a long press on an app, i can edit it(move it, delete it and such)

but the problem is , when i press a long hit to edit an app - a POPUP tells me - "Screen edit locked" .
I searched all over the phone settings , and i dont know how it was made up like this , and how can i restore it to default settings !!!

Please help !
Thanks