the code is :
properties[1]="javax.naming.Context.INITIAL_CONTEXT_FACTORY=com.sybase.ejb.InitialContextFactory"
properties[2]="javax.naming.Context.PROVIDER_URL=iiop://<host>:9000"
properties[3]="javax.naming.Context.SECURITY_PRINCIPAL=jagadmin"
properties[4]="javax.naming.Context.SECURITY_CREDENTIALS="
TRY
conn = CREATE ejbconnection
conn.connectToServer(properties)
catch (remoteexception re)
MessageBox("exception", re.getmessage())
CATCH (createexception ce)
MessageBox("exception", ce.getmessage())
catch (namingexception ne)
MessageBox("exception", ne.getmessage())
catch (exception e)
MessageBox("exception", e.getmessage())
END TRY

there some error occurs when it runs:
'unknown exception thrown from a pb extension'
why?