8 bit Problem ?

I am running Informix 7.22 Online with GLS (Traditional Chinese). Recently, I have to transfer a database to our server. When I import it, I alwayse have the "Illegale Character" or the column number is not right problem. I think the problems are due to the database contains the mistyping functions keys or the data contain the delimiter symbol. My question is : Can I filter the database first ( I mean to filter the illegal function keys ) ? If I can do it first, can you tell me how to do it ? Thanks in advance.