I am getting the following error when trying to install a soho plugin. I have no problems unzipping the file, so I'm guessing it's #1 that's the problem. Any help?

Error: Could not successfully extract zip file (quickedit_dropdown-1.6.zip).
Possible causes/fixes...
1. shell_exec() function disabled on your server - Chances are if this is the cause then you'll probably have problems with the Software Updates feature as well. If that's the case, you may want to ask your web hosting company about whether "the php function called shell exec is disabled" on your server.
2. Damaged archive file - You may want to check whether the .zip archive file itself is incomplete/damaged. To do this, use WinZip or similiar utility on your local PC to open up the plugin .zip file you downloaded... If the .zip opens in WinZip with no error message, and you can see all the files and folders within the .zip, then the archive is probably OK. Otherwise, if you do get an error when you try to open the plugin .zip with WinZip, then try re-downloading the plugin .zip, or contacting the plugin author if that doesn't work.

I submitted a support ticket and they enabled shell_exec() which fixed the problem.