You don't go uploading all the files from the subdirectory into your forumhome directory. You should just upload the contents of the upload folder (ie., the 3 directories 'admincp', 'includes' & 'modcp') to your forumhome.
In the zip-file:
upload
- admincp
--- file1
- includes
--- xml
----- file 2
--- file3
Would become on you server:
forumhome
- admincp
--- original admincp files
--- file1
- includes
--- xml
----- original includes/xml files
----- file 2
--- file3
--- original includes files
etc....
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