Problem with JsPDF and nodewebkit export

I'm having a problem with node webkit exported. When I try to save the pdf file using JsPDF this message appears:

Uncaught node.js Error

TypeError: undefined is not a function

at l.vm (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:364:450)

at g.Pl (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:197:159)

at a.tj (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:190:126)

at a.$a (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:189:308)

at l.fr (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:124:210)

at l.cm (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:123:304)

at l.Vo (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:122:376)

at l.trigger (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:122:281)

at m.On (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:346:24)

at d.Vf (file:///C:/Users/Vini/AppData/Local/Temp/nw8708_29817/c2runtime.js:357:64)

What i'm doing wrong since it worked on the construct preview?