for more specific info on this artefact and how to address it....the free and open-source application Virtuadub AVI editor has a VERY useful section in its help file named 'artefacts', in there is a great read for anyone looking to convert or repair vids.
..This was NOT an advert for Virtuadub.
yep - its a conversion error - specifically a 'color-space conversion error'. field-Lines in one codec type don't match the lines in the flv-codec base. The bottom line? = the clip needs to be re-converted [to a basic, common codec like _divx_ or similar] then re-uploaded and checked again... I really hope it works for you I love this clip ;)
..This was NOT an advert for Virtuadub.