Baber, I did what you suggested. Lets see if they again hit it or not. The problem is that its occasional the same field SSRS doesn't complain most of the time.
Sohaib yes I followed this article. So are you saying that Microsoft doesn't support adding VB code to the code section anymore in SQL server 2012 ssrs ? then why its there in the first place?
No Raj it dint work same error.