The kit was purchased from Dension USA on 6/6/06 (maybe this is unlucky?).
The part number is I-BMW-T. The barcode reads A00014-0606. There was an additional number on the upper right hand corner of the label (dl-1002) that might or might not mean anything significant.
I didn't think that I installed it incorrectly either; I've got a decent EE background, and the install was as basic as it gets. Could've still made a stupid mistake, though I can't see how...
Thanks, Tom! I owe you virtual beers.