Problems with installing Joomla (cannot unzip uploaded files) on webspace

[#1]

Hello,
We were trying to install a pre-made Joomla template on our CGI webspace, but we keep running into problem every step of the way. The biggest problem now seems to be that we cannot unzip either the backup or joomla installation on our CGI webspace. We are advised by tech support that we should unzip the files locally, and then upload all of those uncompressed files.
We are unsure why, but this does not work. When we tried to unzip & upload a straightforward Joomla installation, we run into difficulties explained exactly like here
http://forum.joomla.org/viewtopic.php?p=1951342
and that article also suggests that the only workaround is that we upload the ZIP file into CGI webspace, and extract it there.
Could anyone think of the way that we can do this? Or, if it can only be done by plus.net technicians, we have the ZIP file uploaded, could you just unzip it straight there please? There's only one zip file there (joomlapack backup file).
Thank you

[#2]

Not sure what that reference means by files being corrupted when uploaded after local unzip. Does the package contain binary files that your FTP client doesn't recognise as such, uploading them as ascii? That will lead to corruption?
David

[#3]

Apparently, some of the files get corrupted when done through an FTP transfer, if the Joomla package is previously unzipped and then uploaded through FTP. A lot of people seem to recommend that we should always upload the zip file, and then compress it on webspace. All webhosts usually offer a Control Panel with File Manager so that the users can unzip the archives uploaded to their webspace, but we couldn not find this functionality on plus.net webspace, and tech support didn't know if anything like that is available.
I know it sounds perfectly reasonable to say that unzipping the files locally and FTP-ing them should work just fine, but it's the fact that it is not, unfortunately, and the very same Joomla pack works without any problems when uploaded to another webspace as a zip and unzipped on it.
I even tried creating the small php script, uploading it and running it

<?php
exec('unzip site-konji.rs-20100315-154227.zip',$ret);
?>

but it didn't do anything, so I take it that PHP is running in safe mode. Fair enough, but surely there must be some way that users can extract zipped files uploaded on their webspace, right?

[#4]

We're not in safemode, I've run a very small exec test and it seems to work fine. I did notice that unzip was missing last night but it has since been installed. Do you get anything in $ret ?

[#5]

Nope, just a completely blank page. And when I refresh the FTP, I can still see just the

/cgi-bin/
site-konji.rs-20100315-154227.zip
unzip.php

[#6]

Hah, I managed to extract it. It seems that even the first zip file got corrupted in FTP. I uploaded another zip and managed to extract the contents OK.

[#7]

Ahh cool, I was about to say that I just tried it myself and it worked ok