Hey Justin,
As with all joomla extensions messages are stored in administrator/language/en-GB and language/en-GB in the en-GB.com_hotspots.ini file.
You can use the joomla language override feature to override any strings in there:
docs.joomla.org/J2.5:Language_Overrides_in_Joomla
I think that in your case you need to modify the COM_HOTSPOTS_N_ITEMS_UNPUBLISHED message. But now that I think about it. If you have set the Hotspots to not be auto-approve we generally need a better message for the user. I'll look into this and do what is necessary to make this better. (until then you can of course change the string)
Regards,
Daniel