I'm not a member of zymic, so i have no idea when or if this will be resolved.
But if you surf the web for ftpzilla, cuteftp, ws_ftp95 le.
download and install, than i can help you more.
I used to use the upload manager, but when i first used an ftp program, i swore never to use an upload manager again.
The files you can upload is to limited with upload manager.
They upload manager doesn't upload the directory structure. (with the upload manager you have to create the directories first and upload after.)
It is a lot slower than any ftp program.
Ftp => Can upload complete directories, without problems. FTP Program keeps your directory structure while uploading. You can CHMod the directories via the ftp program, and you name it.