Newbie question

Dear Macports Users, I am newbie to macports and even to the terminal. I needed gtk2 for compatibility with RGtk2 (a R stat software package). I thus installed mac ports (from binary), and port install gtk2 without any problem. However, when trying to to install the R package (within R, of course), no GTK was detected (and installation failed). Checking the path in my ~/.profile gives: export PATH=/opt/local/bin:/opt/local/sbin:$PATH Thus, my --certainly-- basic question: what's wrong ? How can I check that gtk2 was correctly installed (port installed indicates gtk2 was installed) and accessible ? Thanks a lot, Matthieu Dubois