It took me almost 2 hours until I realized whats wrong. I have tried to put the libraries in the Book Designer folder (C:\BD) etc....
This one is what helped me... (ran in the C:\windows\system32 folder on vista)
regsvr32 /u comct232.ocx
regsvr32 comct232.ocx
So everyone who has problems to show the dialog window of LRF export, run Process Monitor, find BookDesigner.exe and find what files / libraries are loading (or not loading). If you are not sure, post here your log and I will try to help you.
Here's the Aero proof :-)
BTW: Im running the latest BD update (July - Bookdesigner2007-07-30.zip)