First of all, i am DBA and not app. developer, so please forgive me if i told something wrong

We have JAVA app on Websphere 5.0 who is accessing DB2 on z/os through DB2 CLIENT. DB2 client is on version 8.1.14. DB2 on z/OS is also v8.

Now, our app developer said to me that is "something wrong with db2 driver". He said that is missing method in SQLJ.zip. He said that "everything works fine with DB2 7.2". In short, he thinks that is "missing method" here.
Any help will be great

This is error code here:

0;ActionID=][CLIENT][ERROR[Execution of EJB transaction Name=PNZ.OST020 LogicName=null failed.
class hr.fina.framework.common.business.BusinessObjectEx ception: FRMTR930019E - Unexpected error while executing ejb transaction.
at hr.fina.framework.common.business.ejb.EjbBusinessO bjectRunner****n(EjbBusinessObjectRunner.java:95)
at hr.fina.pnz.os.transaction.os.OST020Bean.execute(O ST020Bean.java:63)
at hr.fina.pnz.os.transaction.os.EJSRemoteStatelessOS T020_dd90256a.execute(Unknown Source)
at hr.fina.pnz.os.transaction.os._OST020Remote_Stub.e xecute(_OST020Remote_Stub.java:275)
at hr.fina.pnz.os.transaction.os.OST020EjbCaller.call (OST020EjbCaller.java:45)
at hr.fina.framework.client.business.router.ejb.EjbRo uter.routeBusinessObject(EjbRouter.java:92)
at hr.fina.framework.client.transaction.TransactionMa nager.executeTransaction(TransactionManager.java:1 44)
at hr.fina.platni.nadzor.web.actions.TestAction.execu teAction(TestAction.java:113)

From this it's impossible to know what's going wrong.
Given your "developer"'s reaction though, he's almost certainly using some internal classes from an old driver.
This is his problem, internal driver classes should never be used if it can be avoided, or if there's a need to restricted to as few places as possible because they can change without notice.

He'll have to fix his shoddy (almost certainly) code to not rely on those classes.