Xorg crashed with SIGABRT in miResolveColor() on logon

[MaraLS]

Crashreport appears just after password confirmation

ProblemType: Crash
DistroRelease: Ubuntu 14.04
Package: xserver-xorg-core 2:1.15.0-1ubuntu7
ProcVersionSignature: Ubuntu 3.13.0-19.40-generic 3.13.6
Uname: Linux 3.13.0-19-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
CrashCounter: 1
Date: Tue Mar 25 22:06:32 2014
ExecutablePath: /usr/bin/Xorg
InstallationDate: Installed on 2014-02-20 (35 days ago)
InstallationMedia: Xubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140219)
ProcCmdline: /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
ProcEnviron:

Signal: 6
SourcePackage: xorg-server
StacktraceTop:
 miResolveColor ()
 FakeAllocColor ()
 ?? ()
 ?? ()
 miPointerUpdateSprite ()
Title: Xorg crashed with SIGABRT in miResolveColor()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1287090, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.