Terminal won't start up

Recently, I was trying to install the toolchain for iPhone development on my iMac, which is on Leopard. Everything was going fine, but at some point, with no commands running, i closed terminal (quit). Now, when I open Terminal, nothing appears on the login window.

I have no idea what's going on, so if any of you have a suggestion, please post it.

Thank you very much in advance.

Does any text appear? Does the cursor show up? Give me some details.