rpmdatabse error in installation

[garima cse iitb ac in]

i m trying to install a relocatable rpm package as non root user.
i copied rpm database files from /var/lib/rpm/ into a directory rpmdb in
my homedirectory(/users/extra/plusers)
when i give 'rpm -i --prefix $HOME --dbpath $HOME/rpmdb packagename.rpm'
command the following errors are shown and installation terminates.


error: cannot get exclusive lock on /users/extra/plusers/rpmdb/Packages
error: cannot open Packages index using db3 - Operation not permitted (1)
error: cannot open Packages database in /users/extra/plusers/rpmdb

can someone plz help me out to install the package.

thanks