transmission-gtk installation issue

[vishnu vardhan <vishnuvardhan.linux@gmail.com>]

lenny 5.0.3
today i have updated the system by the following commands :
aptitude update
aptitude full-upgrade

I tried to install transmission-gtk. But it has shown the following message :

The following packages are BROKEN:
  transmission-gtk 
0 packages upgraded, 1 newly installed, 0 to remove and 51 not upgraded.
Need to get 698kB of archives. After unpacking 2798kB will be used.
The following packages have unmet dependencies:
  transmission-gtk: Depends: transmission-common (= 1.76-1~bpo50+1) but it is not installable
The following actions will resolve these dependencies:

Install the following packages:
transmission-common [1.22-1+lenny2 (stable, stable)]
transmission-gtk [1.22-1+lenny2 (stable, stable, now)]

Score is -9949

I have uninstalled the transmission-gtk before attempting to install from backports.
Please suugest me.

thank u.