If you are using the Simplified Chinese code page, you might need to upgrade by moving all clients and servers to version 7.0.1 at the same time.
Version 7.0 and later supports only the CLOB datatype in Oracle. For environments that use Simplified Chinese, version 2003.06.15 and earlier supported only the LONG datatype, not the CLOB. Because of this incompatibility, clients from version 2003.06.15 and earlier cannot work in an environment that includes clients and servers from version 7.0 and later.