Preview in Browser Error on Mac OS 10.2.8

Hello:

Finally, I completed the dynamic page tutorial. Now trying to view in diff.
browsers by doing "Preview in Browser". Then I'm getting this error message:
"
Unable to launch
Macintosh HD:Application:Internet Explorer.app.
Please be sure that this application exists and that there is enough memory to
run it.
"
I did "Preview on Browser" on diff. browsers, then I got these results:
1. All Netscape, Safari and IE have the same problem sometimes when they are
the first time to launch.
2. IE comes up with its home page and always has problem to open the page
created in Dreamweaver. It shows this error message ?A connection failure has
occurred.?
3. Safari comes up with it home page first then open up a new window to show
the page created in Dreamweaver.
4. Netscape always comes up with the desired page created in Dreamweaver.

System info:
Mac OS 10.2.8
Safari 1.0.3
Netscape 7.2
IE 5.2.3
The default browser is set to Safari.

Is it a bug on DW MX 2004 or on IE?
Does the behavior of "Preview in Browser" option do anything with the browser
setting? If so, what and how?

I saw in Safari > Preference > General > Default Web Browser, there is Opera
6.03. But I don't see it in Application folder. Does it come with Mac OS
10.2.8? If so, how can I activate it? If not, where I can get it?

Thanks in advance.

Pw