Re: What does this message mean when trying to install WEKA 3.8.4?
For some reason, the file for a DLL that is part of the Zulu JRE (which we include in Weka 3.8.4 and 3.9.4) cannot be opened for writing.
The most likely explanation is that the Weka installer program for Windows that you have downloaded does not have write permission to the Program Files folder hierarchy when you are running it. Normally, the installer needs to run with administrator privileges for this to work. See also the second solution given at