ORA-27062: could not find pending async I/Os
Cause : There should have been some async I/Os in the system but a blocking aiowait indicates that there are no more I/Os. It could be either because of an Oracle bug or the vendor OS bug or due to a NFS server not responding
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
check Oracle trace file, OS message files and contact Oracle Support
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.