There is no flaw in
Infrastructure Manager, the error is caused by a 'size rule' on the webserver. To work around this, you will have to navigate to
http://archive.nimsoft.com and download the desired zip from there.
Please then import the probe package into
Infrastructure Manager using the import function via the context menu (right-click -> import). Please be aware that you cannot simply copy the probe package into the archive folder, this must be done via IM.