调用write时参数数量或者类型错误

有一个存储过程，进行blob的写入操作，在dbms_lob.write(picblob,vLength,1, BLOBDATA);
此行编辑时提示错误：调用write时参数数量或者类型错误，这是从网上找的，
我的数据库是oracle 8.17,工具为pl/sql developer 5.1.2.682,谁能解释这是什么原因？


create or replace procedure AddLxj
(
aId in integer,
BLOBDATA in lxjtest.pic%type
)
is
picblob blob;
vId integer;
vLength integer;
begin
INSERT INTO lxjtest (id,dt,pic) VALUES (aid,sysdate,EMPTY_BLOB());
--定位刚插入的BLOB
SELECT pic INTO picblob FROM lxjtest WHERE id = vid FOR UPDATE;
--将内容写进刚插入的BLOB
dbms_lob.open(picblob,dbms_lob.lob_readwrite);
vLength := dbms_lob.getlength(BLOBDATA);
dbms_lob.write(picblob,vLength,1, BLOBDATA);--//调用write时参数数量或者类型错误
commit;
exception

when others then
rollback;

end AddLxj;