I am testing 3.3-beta1 on a localhost running on XAMPP.
With certain zips I get the following error from theme / plugin upload installation:
Unpacking the package…
Installing the [theme/plugin]…
The package is corrupt or not in the correct format.
Theme install failed.
I have all versions from 2.9.2 through to 3.3-beta1 running on the same XAMPP localhost setup.
All plugin and theme installations I am testing with the same zip files work a-okay on other versions.
I have tested zips archived using 7zip, WinRAR, the default Windows compressor, and archives created via cPanel's File Manager. All these failed.
Zips downloaded from the repository work a-okay, but they are the only ones I can find that will install.
After encountering this issue on a XAMPP localhost I setup a test installation online.
I encountered all the same issues online as well.
This is my first round taking part in the beta testing, so wanted to get some feedback before posting it on Trac.