Here is the error: package_no_zlib
I have already had my support look at it and they told me that (zlib) is enabled in the PHP
Another time I got this error: here is what I get using Internet Explorer: Sorry, your PHP configuration doesn't have support for zlib. Without this, the package manager cannot function. Please contact your host about this for more information.
Themes on 1.0 or 1.1 ... I'll assume 1.0.x for the moment.
That error is thrown when PHP can not find the function "gzinflate" which is a server problem, ElkArte is simply looking for a PHP function to use.
Go to Admin -> Main -> Support and credits ... Next to your PHP version select more detailed ... in that listing you should see a Zlib section, if you do no then its not installed or disabled.
For the record, this error is thrown in this test:
if (!function_exists('gzinflate'))
throw new Elk_Exception('package_no_zlib', 'critical');
so, only if PHP doesn't have the gzinflate function.