I have in a virtual environment preformed an update from 1.6.9 to 1.9.4 and to 1.9.5, and each time I was unable to download uploaded files. These were done on clean and vanilla installs.
The errorsome part seems to be:
Where it returns:
One environment is WIn2k3 Server FastCGI+PHP on IIS and the other is Apache2, Debian, PHP5