That is an archaic problem of announcements module regarding the Turkish language.
Your announcement module will work fine if you change your locale to English.
We were awaiting like poor little kittens for the development team to overcome this issue with the new version : )
But unfortunately, it got even worse. : ( The Turkish i ( ı ) problem with DNN core and modules seems to persist.
With versions prior to 4.00 there exists a small hack to make it work with Turkish locale
Change "I" s to "İ" s in the announcement template.
eg./ [PUBLISHDATE] ---> [PUBLİSHDATE]
( this time it wont work with english though. Sorry, no multilingual sites with the core ann. module)
cheers