I am on OS X, using Belle Nuit Subtitler to create a FAB script and subtitle images from my srt. The file format I am using is TIFF-RLE.
When I import my FAB files to Encore, the monitor shows that the subtitles come up with an opaque background, covering the video. Building the DVD has the same results.
I suspect it has to do either with the image file format I am using or with the color mapping that is done before the actual import of the subtitle images.