Using a MakerBot Replicator 1 dual (or clone like FlashForge Creator) with Cura
Edit:  After looking at GPX more I'm not sure what you are doing?  Are you trying to slice something in Cura and use GPX to make the X3G file or use the starting g-code from Cura in Makerware?  The code you posted above is used in Cura to generate the g-code and it appears you should be giving GPX the g-code file made by Cura.

You didn't specify which error you are getting or where but if I had to guess it's from the information in the curly braces. Everything in curly braces "{}" is a variable in the slicer used to generate the g-code.

All the information below is useless to the printer and I would start by removing it to see if you still get an error.

; Sliced at: {day} {date} {time}
; Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}
; Print time: {print_time}
; Filament used: {filament_amount}m {filament_weight}g
; Filament cost: {filament_cost}


If you still have an issue after removing that then you could remove {print_bed_temperature} and {print_temperature} and hardcode those values to something to see if the process completes.

If it's successful at that point then look at a different starting g-code and find those variable names and replace them.