At windows 7 64bit, when i connected another screen (two screen at resolution) I open PDFTKBuilderPortable, and it don't show the main window. it was hidden. when i disconnected, and remain with only one screen, the program work normal.
This bug don't happen at windows 8.1 64bit.
If that is the case, it is a base app issue, not with our portablization.
On my PC, I can fire up PDFTKBuilder and have it work fine on my dual screen Windows 7 64-bit setup.
Note that connecting a second screen while an app is running can often confuse it, so you may have to start it up after you connect/disconnect a screen.
Sometimes, the impossible can become possible, if you're awesome!