typo and menu problems in MakeNSISw

1. The messagebox that pops up if no NSIS update is
available has the title "NSIS pdate". The "U" is missing.
2. In NSIS 2.16, the drop down toolbar item for setting
the compressor no longer drops down. It works in NSIS
2.15. I suspect that the reason it is broken is the new
"Cancel compilation" menu item.