I don´t know whats wrong with you all.
Simplymaya IS ALREADY the best page for MAya users and you still cry for nothing.
I ever get FAST, PROFESSIONAL AND FRIENDLY answers!

It´s too SimplyMaya :

Select the first curve and open the Planar menu then set the output Geomitry to Polygons, Type to triangels, tesselation method to standard fit and set the 3D delta to a smaller value as the preset ( like 0.0170) and planar!

Select the second Curve and hit G for repeating the last action!

Then you should have two fiting planes in the shape of your Guitar!

Then open the outliner (Window- Outliner) and select the two curves and loft them! Do the same modification like the planar.
output Geomitry to Polygons, Type to triangels, tesselation method to standard fit and set the 3D delta to a smaller value as the preset ( like 0.0170) and planar!

Last but not least delete the two Curves if you want and it is done.
Easy or not???

Good luck and a good work!!!