I didn't stare too hard at the above results, but skim and starting typing. Something like this is best portrayed using graphs. Graph the best fit line overlaid on a scatterplot for the continuous variables. Next, do the same thing, but dichotomize the IV based on the categorical variable. Now make the points on the graph coordinate with the group they are in and plot the lines generate from the interaction model.

This should help you understand what may be occurring. Also, feel free to post these graphs so we can also learn and evaluate the effects.

Thanks.