Plug-in Alert on Mozilla

Hi to all,

I have a Mozilla 1.7.12 running on a sparc solaris 8 workstation.
My system administrator don't want to install the Macromedia Flash
plugin but it isn't a problem for me.
So, when I load a page in which Flash plugin is used, annoying plugin
alert appears. The alert is titled "Default Plugin" and says "This page
contains information of a type (application/x-shockwave-flash) that can
only be viewed with the appropriate Plug-in. - Click OK to download
Plugin".

Is possibile to avoid this alert to appear?

Thanks in advance.