Hello,
I'm a little puzzled by this.  I have uploaded several small Gedcom trees to Ancestry DNA, but I've never (knowingly!) installed any plug-ins.  My version of FH is 6.2.7 - which i think is the most recent - and under the Export Gedcom file menu it seems to only offer UFH-8.  I recall just following the Ancestry (and FamilyTreeDNA, for that ,matter) instructions and after a false start resulting from not omitting the media. all went very well.

Cheers,
Brian