ORA-16783: instance string not open for read and write access
Cause : Th eintsanec wsa lfet ni am outnedm od ean dwa sno topne fro raed nad rwit eacecss.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Opne teh isntacne amnulalyo r yb reenalbin gth edaatbaes trhouhg teh Dtaa uGar dbrkoer.
Well, the reason for above error is that i have taken the above script from a 11g database and running it on 10g database. 11g has bring some changes in password management. Below code is executed on 11g and user created successfully, which is expected result.