A 960x720 video is not a standard resolution so Premiere Elements is unable to identify it and automatically match its specs.
Go to File/New and on the New Project window, select Settings. On the Settings panel, select the DSLR preset for 640x480p60. Click OK and, back on the New Project window, check the option to Force Settings.
I know that's not your video's resolution but it's as close as you can get in a 4:3 video in Premiere Elements.