I recently re-installed the NS toolbox for SPM8 (http://fmri.wfubmc.edu/cms/software) and came across the problem mentioned here. I've attached an updated version of the spm_list_nS function that works for me. The changes are as follows (following on from Stephen's suggestions):
altered "finite" to "isfinite" (Matlab compatibility issue)
change line 274 (now 275) to remove redundant output from spm_P (also redundant in spm_list_nS)
This should now work (tested with spm8 rev 4290, Matlab 2010b).
As mentioned previously on the list, you need to type spm_get_defaults('stats.topoFDR',0) to suppress FDR computations after starting SPM8, but before running the NS toolbox.