About the security manager
The security manager is that part of the browser which controls what
java applets can do on your computer. It prevents the Java applet doing
harm to your files and your personal data. As a general rule, security
managers are written in such a way that they do not allow the applet to
read or write files but on the computer they come from.
For instance, if you view a web page at www.example.net containing
an applet then this applet runs on your computer but can only read and
write data on www.example.net, not on your computer. Thus your
personal data are perfectly safe.
However, there are tiny differences in the security managers of
Netscape and Microsoft concerning applets stored locally on your computer
(such as kPlot if you have installed it locally).
According to my experience, Netscape's Communicator then allows the applet
to read and write on your computer. This allows kPlot to read locally
On the other hand, Microsoft's Internet Explorer does not allow
local applets to read or write on your computer. Thus, kPlot cannot
run locally with this browser.