If 'openpanel' linux user exists, opening OpenAdmin > Security > Firewall will fail on 1.6.2 with error: Invalid tempfile ownership [$file]
due to line:
my (undef,undef,$uuid,$ugid) = getpwnam("openpanel");
in modules/security/csf.pl
If you are experiencing this problem, temporary workaround is to simply rename 'openpanel' with 'root' on that line. This will be automatically resolved in the upcoming 1.6.3 update