Can't Type Password in Terminal

[Graphorrhea]

I'm changing a sudo command in OS X 10.5.6 on my new iMac and I'm running into a problem. Terminal asks for my password (I'm the Admin) and there's a gray rectangular box after the word "password". I'm unable to type anything. I tried typing my password and pressing return. Nothing happens but another prompt to enter my password.

I've repaired permissions after installing the latest updates. I also tried typing in my password before I installed my latest updates. Either way Terminal won't allow me to type in my password.

I wonder if Terminal is corrupt. ?

This is a brand new computer, arrived yesterday, nothing added to it. I'm putting it through the paces before adding my external hard drive and other software.

I purchased software, which requires a sudo command, and that's where I'm having the problem. The software is compatible with Leopard. I know that's why I purchased a new computer. It was a good excuse for an upgrade.

[DeltaMac]

When you are asked for a password in the terminal, simply type your password, and press enter. You won't see your password as you type, and no apparent result until your press the enter key. That's completely normal for the terminal app.