>can you explain what is correct way to fix this problem.

It depends if you've to convert data stored in those tables from CPDBF() to CPCURRENT() or not. If you don't than Tore's suggestion will work for you. Otherwise you'll have to use

COPY TO ... CDX AS nCodePage

to copy to a temp file and than replace original table and CDX with the copy.
In any case create backup copies of your tables before modifying them.