xonix crash after a single game

xonix: cannot reopen high score file
*** glibc detected *** xonix: double free or corruption (fasttop): 0x0000000002065270 ***

the high score file is /var/cache/xonix/xonix.scores, but its rights are 664 (root/games), so default user (which is not in games group) can still launch xonix (/usr/games/xonix : 755 root/root) but when access to the high score is needed, it fails... and crash.

Easy way for fix: chmod 666 on xonix.scores (but maybe not the intended behaviour/protection)
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Architecture: amd64
DistroRelease: Ubuntu 11.04
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027.1)
NonfreeKernelModules: nvidia
Package: xonix 1.4-26
PackageArchitecture: amd64
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LC_MESSAGES=fr_FR.UTF-8
 LANG=fr_FR.utf8
 LANGUAGE=fr_FR:fr_BE:fr_CH:fr_LU:fr_CA:fr:en_US:en
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic 2.6.38.7
Tags: natty
Uname: Linux 2.6.38-10-generic x86_64
UpgradeStatus: Upgraded to natty on 2011-05-20 (52 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare