hi paresh..

I had simulated the same error in test box and succeeded in that,but frustation was what went wrong i can't find.

What i did was..
switched log files on prod, and then worked in standby which repeats the same error.I shut down both dband went out came back open standby alone and made usual recovery that i had done previously.
SQL>alter database recover managed standby database disconnect from session;
SQL>recover managed standby database cancel;
SQL>alter database open read only;
It holds for a while and then opened in read only mode(What a wonder..?)
then i shutdowned standby;
Then went to prod kept in mount state,then standby kept in mount,then opened prod and it SYNC with standby.
!!!!Working properly.

I reported to my boss,and asked for down time for real PRODDB.He too accepted next weekend.
I have made up my mind to do the same process.
I will send you next week the result.

If u have any idea on this regard kindly inform me.What actually went wrong.