Perl/Gtk2 is based on the c Gtk2 libs, so you need to install the c libs before the Perl modules that interface to them. Your linux distribution may have the runtime Gtk2 (Gnome libs) as a separate package, with the "devel libs" in another rpm (or whatever). SO if you can run Gtk2 programs, but can't compile them, install the "gtk2-gnome devel" package.

If that is not possible, get the c libs yourself See Perl/Gtk2 Faq

The basic libs are only needed, not the entire Gnome library set. They must be installed in a certain order

pkgconfig
cairo
glib
pango
atk
gtk2
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You usually have to keep the same pkgconfig location.... defaults to /usr/local, but it's easiest to keep them in /usr, so when you configure them, do

./configure --prefix=/usr
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Get the latest versions from Gtk+ downloads then install in the order above, then install the Perl modules in the same order.