sLaNGjI's, thank you for your kind reply.
My site was working fine before the upgrade using 0.9.2.4. I have also four other sites with 0.9.2.4 and have no problems. My issue is specific to 0.9.2.5. TDF in this tread above had also similar issues with Disk cache.
I am using Litespeed web server. Any pointers are appreciated.