I've never had a problem with versions of patch... if you play online at all custom then you already have a downloads folder in your WC3 files
i think the problem here is that he didnt install it to the default directory... which means:
search for "warcraft III" and "warcraft 3"... if those dont bring up any results then search whatever you think you would have installed it under.
if you only have warcraft 3 with no expansion (frozen throne) then the frozen throne will not recognize it - but as long as it was installed under the default directory and you have Downloaded 1 custom map online IN THE GAME then the c://program files/warcraft 3/maps/download directory does exist
try browsing for it instead of just typing it in...
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i have easily over 300 maps just from in game DLs, about 200 from downloaded and moved(mostly from here), and I've got half a mind to DL about 50-60 more today... this is something I'm use to doing :twisted: (not to mention all those backups and reformatting I've been doing recently)