I had already tried to enable trace. But when I enable trace, report builder crashes!!
I created SR also, and oracle says that they do not support 10.1.2.0.2. I should update to 10.1.2.3.
I installed the 10.1.2.0.2 in xp mode and tried to update with 10.1.2.3. However, the updgrade failed saying that there is no update patch required/found or something like that.