The thing is that installer needs around 1,5-2 GB of free space on the C disk (in Windows case), even if you are installing it on another disk which has plenty of space. Public.zip is being extracted to Temp folder and then its content copied to the installation folder. So, if you have low disk space on C, you will get this error too. I understand, that this must be a nature of many installers and extractors for Windows, to use temporary folder for extraction, but maybe it is possible to tune it to use the destination folder for extraction. This will probably also increase the installation speed (no need to copy things from one place to another). This can be observed by watching how free disk space changes in C and in the destination drive during the installation.