To check what the file really is, in that sample smazuser.dll, put the file on Linux
system and run the following command as root :
# file smazuser.dll
In that sample, the command returns this output :
"smazuser.dll: Zip archive data, at least v2.0 to extract"
This file is a zip file and that's why Windows returns the message
"not designed to run on Windows or it contains an error".