I was wondering which version of PHP/Apache and Joomla you are using to test Hot Spots?
I've tried PHP 5.2, 5.2.11 & 5.3 and have varying success with all (nothing to do with Hot Spots).
I know HS doesn't work well on 5.3 yet, no problem, I want to run Joomlafish as well, but that won't work on 5.3, so I'm using 5.2.11 (But HS doesn't like that either).
So, now I log in to my site using 5.3, then switch to 5.2, that works fine
I can load up the 'Default' map, that works fine. When I try to 'Add Spot' I get the following message:
[li]The image “http://localhost/MNS/index.php?option=com_hotspots&view=all&layout=addspot&Itemid=8” cannot be displayed, because it contains errors.[/li][ul][/ul]
I thought I'd try the same version as yourself and see how that goes.
Cheers, Richard