Are you working with Premiere Elements 11 on Windows?
Did you create the rolling credits via Text Menu/New/Default Roll?
The general principle is, if you want a slower roll, increase the duration of the clip. You can use the mouse cursor to drag out the right edge of the clip.
More you increase the duration, more you will slow down the credits roll, and more you decrease the duration, more you will speed up the credits roll.
You could also change the clip duration with right click of clip, selection of Time Stretch, and in the Time Stretch dialog set the clip duration hours; minutes;seconds; frames Timecode format.
Please let us know if that works for you.
Thanks for your reply.
Dragging the frame out works great.
Thanks for the follow up.
I just added a note to your thread about the green cast and suggested that you look at the Lighting Panel expanded which you will find under Adjust Tab/Adjustments Palette/ in your Premiere Elements 11 Expert workspace.