No, don't try to upload a folder.
Instead, you need to archive that folder in one of 3 formats: zip, rar or 7z.
You can use WinRar to archive to a rar file (choosing Best compression to make the rar file as small as possible)
WinRar is not freeware, but it comes with a trial that really has no limits to it. I guess you can call it
nagware.
You can download WinRar here:
http://www.rarlab.com/
Or you can use 7-Zip to archive to a 7z file (again choosing either Maximum or Ultra compression to make the 7z file as small as possible)
Unlike WinRar, 7-Zip
is freeware. You can find it here:
http://www.7-zip.org/
Both programs can also produce zip files; recent versions of Windows can also create zip files.
Here's how to do it with Windows:
Right-click the folder, point to Send To, and then click Compressed (zipped) Folder.