[Freesurfer] alloc: invalid block

Hi,

I am following the tutorial http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/OverlayFeatStatisticalMa... At this command, tksurfer bert lh inflated -overlay ./fbert1.feat/stats/zstat1.nii.gz -overlay-reg ./fbert1.feat/reg/freesurfer/anat2exf.register.dat -fthresh 2.3 -fmid 3.3 -fslope 1 -annot aparc.annot tksurfer runs OK but when I click on any button between "show curvature" and "draw outlined labels", it crashes and gives this error:

% alloc: invalid block: 0xbb6c80: 0 0 0

Here is the section copied from bugr output: ---------------------------------------------------------------------

FREESURFER_HOME: /usr/local/packages/freesurfer

Build stamp: freesurfer-Linux-centos4_x86_64-stable-pub-v4.0.1

RedHat release: Fedora release 8 (Werewolf)

Kernel info: Linux 2.6.23.9-85.fc8 x86_64

---------------------------------------------------------------------

any suggestions how to correct this?

Thanks,

George