Hey friends..
Thankyou all for your support..
well I found out the cause and its solution..
In my final scene i used Xref manager plugin to Xref 7 files into one..
so after you add the xref links.... a dialog box asks whether IT SHOULD PURGE UNUSED COMPONENTS OR YOU LL DO IT MANUALLY.
HERE YOU SHOULD SAY NO.
hope this might help anyone getting the same error..
Dont let the Xref plugin Purge the unused components...
Instead before Xrefing each file purge unused components in them.
have a nice time...