php & interbase problem.....

Hope someone can solve my problem..... I'm using Interbase as a database. I get error message when I retrieve data from the database (ibase_fetch_row) which contain chinese character. Warning: ibase_fetch_row(): arithmetic exception, numeric overflow, or string truncation Cannot transliterate character between character sets in ......... If I select the record without the field that contain the chinese character, it works...... The datatype for the field that contain chinese character is varchar(20). (I use program written in Delphi to enter the data into the database and now I want to use php to retrieve the data)