I can probably be your machine. I haven't used Final Cut in years now... I only use adobe programs. Since I make animations with Adobe Flash I find Adobe Premiere to be the best bet for me. I've done plenty of video editing for customers too with it and it's been a rad experience. But like I mention, if you're getting corruptions, it must be your machine, and here may be some common reasons:
Your memory ram is too low: How much ram do you have? - If you have low ram, try closing all your browser windows, and any additional programs to free ram space.
You may not have enough disk space: Have you checked? - Some files are render very big. Use H.264 format. It compresses the movie to a small file while maintaining HD. Newest format for online streaming.
These are the main issues. The processing speed can be an issue as well, but only if the video is high on effects.
So, answering some of these basic questions can help you understand what's up.
I'm a f*****g geek, so I hope I helped - I'm just gaining knowledge on s**t all day and weight.... I promise that if i hit 180 pounds I'll go jogging....