I am really in trouble...

In my company we have three database

Our company is product based,and we have already set up in DB2 and Sybase,but our some client want in Oracle,so I change everything in oracle.

but now we are using cluster table and Indexes in DB2 and Sybase,so samething i did in oracle also.

now the thing is that in DB2 and sybase they already used cluster table and Indexes because of Performance problem.I am using cluster table and Indexe in oracle but it's giving me two errors
2.Can't serialized(Error: ORA-08177)

In db2 and sybase its work fine,but in oracle its give me above errors.

If I am removing the cluster table and indexes in oracle then this both error are automatically removed.

But I dont know about the performance in Oracle,if I am removing cluster table and Indexes in Oracle there is any problem with the performance!!!!!!!!!!!

see at present we are working on development stage,and when it will go to Production stage what you think IS any problem with the Performance!!!!

And I have to take Decision URGENT!!!!Can u sugget me what I want to do?????