Thought I'd add a note. I am experiencing what appears to be the same issues. I am using VideoPad 3.14 (registered).
Crashes happen seemingly random, (possibly while rendering/generating thumbnails?). Sometimes, while playing my unfinished project VideoPad will lag really bad (play sound but not video), possibly related?. closing the project and using "Clearing unused cache" works, but only for 10 minutes or so then it starts crashing again...
Windows 7 64Bit, (Fresh install, completely updated).
8 core, 3,5GHZ AMD FX-8320. Note! videopad was not crashing on my old, Intel core-2 duo.
Radeon HD7750 videocard (with new/updated drivers.)
 This is the first time this has ever happend. I just played my video and a black line appeared under the sound track (as it was playing), solid is where the video played smoothly, but the gaps are where the video froze but the sound continued to play smoothly. note that it changes, sometimes the entire thing plays smoothly :/