warning with DB2/UDB enterprise stage

[yimwai]

I find the same warning with DB2/UDB enterprise stage in some jobs.
warning information is
"Invalid character(s) ([xF7]) found converting string (code point(s): ) from codepage GB2312 to Unicode, substituting."
AND
"ExecuteImmediate issued Warning for:?"
even when no result data come into the stage,the warning still shows.
what possible problems can cause that?IF you meet the same warning?

[ray.wurlod]

It's very odd that a single byte is being reported as a problem in a two-bytes-per-character code set (GB2312). Does your row contain an odd number of bytes?