Sorry for delay, I was to busy.
I look regional settings of the account under witch the SQL server is running and I found source for my problem . Settings was wrong - US (probably default), when I set regional settings for this account to Slovenian, XP_CMDSHELL 'DIR...' return date in dd.mm.yyyy format.
My backup solution now use the myDir.vbs, is more universal, work even if regional settings are wrong.
So, we solve problem. Thanks again.
Regards
Uros