[Wine] Unable to write a log file

[LMNOPLMNOP]

I'm trying to run Brainvision Analyzer software through wine on my mac (OSX Snow Leopard).  When I enter my registration info for the software, I get an error message:

File Write Error
:\Users\...\license.txt

where "..." is a path to a folder that contains license.txt, but the file is unchanged when I run the program.  Any idea why the program can't write to the file?

The program's documentation suggests that I could circumvent the problem by writing the license info to license.txt myself.  I tried writing it with a mac ascii editor to no avail: I'm still prompted to enter my info when the program starts.  Any ideas?