problem opening design matrix

[grey pendleton]

I'm having trouble with MARK aborting when I try to open a design matrix. I haven't found this post previously, but I could have missed it. The problem does not happen all the time; sometimes a dataset/analysis will be fine on one computer but not another or won't work on a computer at one time, but seems to work ok later. All computers I'm using run WinXP. The analyses I'm running are not large.

Any suggestions would be helpful as it happens often enough to be a nuisance.