give us a paragraph or two of EVERYTHING you ARE doing.. everything you KNOW, everything you THINK... and where you are most unsure of yourself...
that will make it a lot easier to help you then giving you a paragraph of EVERYTHING you should already know, which I don't have time to do right now. I'm running some halloween banners to my Mimaki, out of Flexi right now, so I MAY be able to help you, but I don't even know where to begin yet.
what you sending? rastor images? vector? Created in Flexi? imported?
are you familiar with the "contour" button, near the lower right corner of the advanced tab? (in the rip and print window) This is where some of the contour cut settings are, but the cutline also has to be designated as a "contour cut" in Flexi first.
Under the "arrange" manu, after selecting your contour (set to no fil, no stroke) go to "contour" and choose "make contour". If this is greyed out, you might first need to click on "convert to outline" also under the "arrange" menu in Flexi.