The only way I can duplicate this is with a user added taxa, which do not have a taxon group. Is your example a user added taxa ? I can't find it in the current Dictionary. It might also occur with other taxa which are missing entries in various tables. I have fixed the Taxon group issue and new version of the OCX is attached. I change the addin to cope with other situations, but if we can identify specific taxa it might be best to get the Dictionary fixed.
Unzip the file to a suitable folder. Remove the previous addin via Tools/Install Addin Module/Remove. Close Recorder 6 and open it again then install the new version of the addin. If this doesn't work try moving the .ocx into the addins folder of R6, then try the install again.
Littlefield Consultancy - IT Consultants