make sure you have jre & ia32-libs-gtk installed, if not install them as root
Code:
aptitude install  default-jre ia32-libs-gtk
run install.pl from extractd directory (e.g.: /home/malayo/zdesktop_7_1_2_ga_b10978_linux_i686/)

run below command as your current user:
Code:
su -c 'perl /home/malayo/zdesktop_7_1_2_ga_b10978_linux_i686/install.pl'
just press enter/return for all the questions

run below command as your current user:
Code:
/opt/zimbra/zdesktop/linux/user-install.pl