it was just on test DB, if i did this test http://sqlblogcasts.com/blogs/tonyrogerson/archive/2006/11/10/1280.aspx and after appeared error with FULL

BACKUP LOG and when I wrote command dbcc shrinkdatabase ('Your-Data-Base-Name', TRUNCATEONLY) it showed error like this topic

after I found this site, where I first tried very inelegant way, how someone writes and it worked, then i could do this test and it worked.

http://stackoverflow.com/questions/56628/how-do-you-clear-the-transaction-log-in-a-sql-server-2005-database