Make sure your video editor is fully updated through Help - Updates
tab. They usually release hotfixes to such issues. If that won't solve your issue then I'm afraid you either will have to switch to a more competent video editor such as Adobe Premiere.
Or install free transcoder called the Handbrake
, and put your Fraps videos through it first before using them in the video editor. Handbrake will re-encode your video into more video editing friendly size and format without touching the video quality. The single disadvantage of the Handbrake is that it's an extra step in your working process.