Couple of things you can do. First thing I would check are your Import Settings, under the Edit tab, > Preferences > Import. Make sure that the setting isn't set to 0:00:00:01. I prefer to set mine to 'Length of Compostion' but if for some reason you need them to be set to 30 seconds you can do it here.
Also, in your composition, you could select the layer of your 1 frame footage still, move the Current Time Indicator(CTI) 30 seconds forward and press "alt = ]", that will extend the end point 30 seconds. Pressing "alt + [" will move the in point to the CTI position.
Johnny Cuevas, Editor
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.