Failed to extract source : Uncompression failed :
/bin/tar: roundcubemail-0.8.2: Cannot mkdir: Permission denied
/bin/tar: roundcubemail-0.8.2/.htaccess: Cannot open: No such file or directory
/bin/tar: roundcubemail-0.8.2/bin: Cannot mkdir: No such file or directory
/bin/tar: roundcubemail-0.8.2/CHANGELOG: Cannot open: No such file or directory
/bin/tar: roundcubemail-0.8.2/config: Cannot mkdir: No such file or directory
/bin/tar: roundcubemail-0.8.2/index.php: Cannot open: No such file or directory
/bin/tar: roundcubemail-0.8.2/INSTALL: Cannot open: No such file or directory
…
/bin/tar: roundcubemail-0.8.2/bin/update.sh: Cannot open: No such file or directory
/bin/tar: Exiting with failure status due to previous errors
… failed! See the error message above for the reason why.
This is an old post, but since I had the same problem I will share how i fixed this.
My website (for example, domain.com) was installed under is own user. home/myuser/public_html was al in group www-data.
Apperantly (unless you give everything 777 rights from public_html to your webmail folder), the user I was logged in with in virtualmin (root) did not have enought rights to write to this dir. So I added the root user to the user group of my domain (myuser) and to the group www-data, which I assigned my domains ownership to.