No :)
Same folder structure, import via drag & drop. One file less: 12924. Stopped right one file before that one I've sent.
Error log:
6 errors:
2009.09.17 17:06:15 - System.NullReferenceException: Object reference not set to an instance of an object.
at MyPhotoIndex.Utilities.ImageMetaData.IPTC.ExtractIPTC(Stream fs)
after them 34 errors:
2009.09.17 17:07:27 - System.OverflowException: Value was either too large or too small for a UInt32.
at System.Convert.ToUInt32(Int32 value)
at MyPhotoIndex.Utilities.ImageMetaData.ExifExtractor.convertToInt32U(Byte[] arr)
at MyPhotoIndex.Utilities.ImageMetaData.ExifExtractor.buildDB(PropertyItem[] parr)
at MyPhotoIndex.Utilities.ImageMetaData.ExifExtractor..ctor(String fileName)
I think let's put away this mystical problem for now. You could add some recommendation "Don't import thousands of files at once -- some strange errors sometimes occur" somewhere in help file. Of course, you should fix it before selling the software as an alternative for some Adobe product, but I guess that's not the nearest future 
. But you never know!
Two more notices for this beta build:
- tag multi-select "flickering" fixed
- folder view "select->shows files from the folder selected" feature vanished. Again -- vanished only for that huge amount of folders I tried to import at once. If I import 1 --20 folders at once -- everything's OK (haven't tried more than 20 for "small amount testing").
Guoda