DBCO connection test error

Hi, All

I defined db connection with DBCO and I configured tnsname.ora.

I test tnsping and logon remote DB using sqlplus.

both are OK.

but!!

I check DBconnection with DB02 and then occured error.

next test connection is OK.

so the CBO program use the DBCO is failed at first time and the next execute is OK.

we use ECC 6.0 , Oracle 10.2.0.4, kernel 185

I attach dev_w log

==================================================

B Connect to EBIZPRO as kbizpro with EBIZPRO:KO16KSC5601

C *** ERROR => Characterset 'KO16KSC5601' not supported.

http://dboci.c 2371

C *** ERROR => OCI-call 'OCIErrorGet' failed with rc=100

==================================================

we use characterset 8500

how can I do?/

thanks