http://bugs.winehq.org/show_bug.cgi?id=28359
--- Comment #3 from Sam Morris sam@robots.org.uk 2011-09-13 11:55:39 CDT --- (In reply to comment #2) Ok, disregard that. I had a copy of dotNetFx40_Full_x86_x64.exe in the current directory. I guess the installer saw it and altered its behaviour.
If I run the installer with a fresh WinePrefix, it downloads dotNetFx40_Full_x86_x64.exe, then exits without displaying any error messages as described before.
If I run it a second time, it actually gives me the error with which I started this bug report.
+wintrust logs from both runs forthcoming...