YUM UPDATE stuck forever

YUM UPDATE stuck forever

I created repository for RHEL 5.6 . There was already an exiting repository for RHEL5.2 which I deleted.
And i run following commands yum clean all yum clean metadata
then, Yum list all It list all the packages.
But when I type YUM UPDATE. It shows
Setting up Update Process
Setting up repositories
rhel-local                100% |=========================|  951 B    00:0
Reading repository metadata in from local files
primary.xml.gz            100% |=========================| 1.1 MB    00:0
################################################## 3229/3229
Setting up Update Process
Setting up repositories
Reading repository metadata in from local files
And thats all folks. Further there is no response from YUM UPDATE.
Any idea