Query Item Refnce error in Cognos 10.2.1.1

[nishant.thakar]

Hi Gurus,
After applying Fixpack C10.2.1.1 my reports started failing.
After investigating came to know that the self Query Item reference is failing.
For Example
I am have Q1 as Query Subject and QI1, QI2, QI3 and  QI4 as query items.
In the above query subject if suppose QI4 = QI1 +QI2 then the query is failing.
Please help!

And it is throwing report server not responding error.

Thanks and Regards,
Nishant Thakar