Hey! Firstly see the screenshot of the problem: http://saymon.biz/wp-content/uploads/2012/08/substr.jpg
it is happened due to substr() usage in function avia_backend_truncate()
I want to ask you to use mb_substr() instead of substr() because just substr() returns an corrupted unicode string in case of, for example, Russian language.
This is applicable in all other cases of usage substr() function