I have released version 5.10 of ADIF to DX4WIN, you can get it here:
http://dx4win.ad1c.us/adif2dxq/
Here are the release notes:
Ver 5.10 - 17 October 2011
Allow group numbers up to 65533 for DX4WIN 8.0x
73 - Jim AD1C
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Jim Reisert AD1C, <jjreisert at alum.mit.edu>, http://www.ad1c.us