Mathcad 15 unable to read files on newer machines

Hi,

I'm using Mathcad 15 (M005 [MC15_M005_20101105]) which has problems reading files (m x n matrix seperated by tab) on computers newer than approx. 18 months. Every way to read files doesn't work (in this case readprn, but other functions show the same behavior). The very same xmcd file on older machines equipped with the same software works very well. I wasn't able to find a solution or workaround to this problem at google or this forum, not even the problem itself. Is anybody aware of this problem and is there a fix / workaround?

Thanks,

Ronny