Windows installer for x64 fails on Vista

Versions 1.20 and 1.30 fail the same way. This might be the problem (from the install log):

Action 15:47:53: PrepareDlg. 
Action start 15:47:53: PrepareDlg.
Info 2898. For WixUI_Font_Normal textstyle, the system created a 'Tahoma' font, in 0 character set, of 13 pixels height.
Info 2898. For WixUI_Font_Bigger textstyle, the system created a 'Tahoma' font, in 0 character set, of 19 pixels height.
DEBUG: Error 2858:  The data for the bitmap Bitmap is not valid
The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2858. The arguments are: Bitmap, , 
Action 15:47:53: PrepareDlg. Dialog created
Action ended 15:47:53: PrepareDlg. Return value 1.

followed by (near the end):

MSI (c) (10:60) [15:49:15:495]: Doing action: FatalError
MSI (c) (10:60) [15:49:15:495]: Note: 1: 2205 2:  3: ActionText 
Action 15:49:15: FatalError. 
Action start 15:49:15: FatalError.
DEBUG: Error 2858:  The data for the bitmap Bitmap is not valid
The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2858. The arguments are: Bitmap, , 
  Action 15:49:15: FatalError. Dialog created
  Action ended 15:49:19: FatalError. Return value 2.

If you want the full install logs, email me ...