Encore wants to transcode my footage on import

I'm importing a movie (720 x 480, shot 24p/24 fps) into Encore that has an
effect placed on it in AE7.0. Upon importing I'm told that "File #### is
23.976 fps and needs to be transcoded immediately." Upon transcoding my
work becomes 30fps. I don't want my work to become 30fps. Other times when I
loaded the project w/o the AE effect the project loaded into Encore w/o issue.
Can anyone provide any advice as to what is going on and what I can do about
it?

Additional info:
The AE effect is Enhance from the Film Magic Pro software (similar to Magic
Bullet). The project was exported from AE uncompressed, so the file being
imported into Encore is aprox 150 gb.

Not exactly. Encore 2 and earlier requires a 29.97 frame rate for video playback
within the app. If you export a 24p MPEG-2, the pull-down flags are written to
the file, and Encore can import and play it back without re-transcoding. But all
24p AVI and QT files in Encore 2 will be transcoded on import.

DVD-Video does require NTSC video to display 29.97 fps, but the player can do
the the conversion from 23.976 fps to 29.97 fps, using 2:3 pulldown- as long as
the pulldown tags are in the MPEG-2 file.

If the monitor is progressive, the DVD player can output progressive video
without any pulldown.