I've had a problem with including several times your nsh file. I made some "library" headers for my products, and I use your utils in some of them. But it's working great when I include nfUtils.nsh in all files only once, otherwise some errors occured. The first was about invalid number of parameters for echo in line 42, so I changed ` to ' and it's passed. But then next error occured:
code:
Invalid command: !if${Condition}
!include: error in script: "C:\Program Files\NSIS\Include\nfUtils.nsh" on line 566