Help, please?

I am using Photoshop CS and have been having a lovely time trying out things that have been posted here, but I am having a slight problem. When I go to crop a picture, once it is cropped I cannot seem to put text on it. I get the little square that shows where the typing would start, but when I type nothing shows up.

I did attempt to make another layer and then type, and played around a bit with it but it doesn't want to work. I ended up cropping the picture in Corel PhotoPaint 8, then opening it in Photoshop just to get it to work but it doesn't look as nice IMO.

Thanks.