Thats not ghosting its haloing.
1 Here are some steps to try. lower your strength slider the first one and see how that goes.
2 next adjust the luminosity slider, sometimes more to the right helps.
3 Adjust the lighting slider, if you are using a preset uncheck the box and manually move the slider to see what works.
4 If nothing else works in photomatix then what I like to do is use one of the existing exposures and mask in the sky in that area, you may have to adjust brightness on your original exposure to match your tonemapped version or sometimes tonemapp the single image just depends every image is different.
5 use the dodge and burn tools in photoshop
There are many ways to fix it
Here is a 3 minute edit.
1 duplicated layer
2 created a mask on top layer
3 painted in that area with black
4 on the under layer I created a brightness layer and adjusted brightness to a better match
5 on under layer I created a selective color layer and adjusted the blues, cyan and neutral colors for a better match
6 merged all layers
7 used the burn tool with a low opacity color black and adjusted the mid-tones
Its not perfect but with more time you could make it look perfect..and with the other exposures it would be a sinch.
Hope this helps