When programming themes/plugins, I first test them on a local WP installation I run on my windows laptop.
I edit the files, then zip the folder, and upload it to my local installation using the wp dashboard. Stuff works fine.
Then I try to upload the same zip file to my domain, using the remote wp dashboard (running on some unix/linux). When I try to activate the plugin, I get a "file not found" error - with no info about which file is missing. I cannot delete the plugin/theme either.
So I connect with FTP and try to delete the plugin folder. No go: "553 Prohibited file name".
It turns out, when I create zip files on my windows system, the filenames end up containing backslashes.
When I install such an archive on a wp instance running on linux/unix, the archive doesn't get extracted properly. Files don't land into their appropriate folders, but end up containing backslashes in their names instead.
This creates a huge mess, because I cannot access these files. I cannot delete them. All I can do is rename the folder containing them, but the broken plugins still appear in the dashboard.
This is a bug you must fix.