Different variants of the problem:

1. Have you installed on the hosting MySQL 4.1.21, which is characterized by the presence of this error (http://bugs.mysql.com/bug.php?id=21456).
Ask for a solution to this problem to your hosting administrator.

2. Check the values ​​that are responsible for encoding DB: character_set, or for versions of MySQL 4.1 and above, character_set_server and character_set_database. If you use encodings other than cp1251 (Cyrillic), for example, latin1, sorting the rows that contain Cyrillic characters will be incorrect. You can verify this by querying the database
show variables like 'char%';

To solve the problem set in the file / bitrix / php_interface / after_connect the following lines
$ DB-> Query ("SET NAMES cp1251");

If these steps do not help, then do the transfer system (installation) again, creating a database dump in cp1251 encoding and creating a new database is also encoded in cp1251.

Most likely, you are installing the system at the set UTF8 encoding in Oracle.
Change the value of NLS_LANG, for example, in AMERICAN_AMERICA.CL8MSWIN1251
The parameter value you can register in registers readily Windows, a branch of HLM / SOFTWARE / ORACLE