Logged In: YES 
user_id=917179

I couldn't update comments and didn't have time to figure out 
how I should do it so I hope this attached file will do.

Follow up:

I ran the installer with the suggested /m1 option. The install 
asked for the following directories (in order):

windows 
system
system32
temp
source

All input boxes had default values which seemed reasonable so 
I left them unchanged.

Then the actual installer window showed (as without /m1). 
After submitting the requested information (as reported in the 
inital bugreport) the installer halted when the small window 
titled "installing" showed, at 1% and the file unwise.exe... just 
as before. No question about registring files (besides the five 
windows promting for manual input of directories as described 
above).

No error messages. Just the same behaviour as before with 
some additional directory prompting dialoges at the beginning.