Hi,
If, you are using Joomla 3.2 in Global configuration you will find advanced options for offline mode.
If you are using Joomla 2.5 - those phrases you can change in language file or inside gk_creative\offline.php file.
There is also another way --- use google translator to read this guide also with comments:
http://blog.elimu.pl/8411-offline-czy-s ... t-pytanie/