I am running the example shown here on how to use debugger
http://www.nusphere.com/flash_files/dbg-good_smaller.html
However when I reach the stage where the entry form is being shown after the "Run in debugger" button is pressed I get an empty screen. I can be able to see the form and enter some values if I press the Run button. But I am only getting an empty screen if I press "Run in debugger" and no break points have been set.

I have currently running version 5.0.1

I can't believe that it simply left an empty page upon Run in debugger button pressed.
Did you change any settings from their defalts?
Did IDE show you any error messages?
Did you check Output Window (View->Debug Windows->Output)?
Did you check Error Window (View->Debug Windows->Errors)?

No I have not changed defaults
There are no error messages in the IDE
Output window is showing the html below the php statements
that is <form ....>
....
</form>

error windows is empty.

By the way this is an evaluation copy. Wonder whether this will make the difference.

Yep, it makes sense because evaluating phped v5 since May 3 2007 is nothing more but an evaluation license violation. If you applied a patch to let it work after 14days expiration, you can't blame that some of the functions stopped to work too.