I've got about seven clips from my iphone 4s, ran them through mpeg streamclip to convert to 422lt. Six of them converted fine, to 29.97, but one clip converted to 28.98 and while I can bring it into FCP to edit, I get the green bar and it won't export out. I've tried setting quality to 50 percent, but no go. I can't figure this out, any help appreciated. Thanks.

Try Compressor and manually force the frame rate.