iMac24 (new) - Snow Leopard. CS4 Flash. All up to date.
I converted a 3Ds (simple) to your format. Then I import to stage. It shows the fuzzy box, then a 2D large box of the item, then nothing happens and nothing is on stage.
It gives an error in the output box of flash:
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ERROR: (Swift 3D Importer - File: )
Invalid SWFT file - Import Aborted.
The following JavaScript error(s) occurred:
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no error details are listed.