Help with printing Frabjous pieces

I'm trying to print a Frabjous (mathmatical sculpture) which is actually made up of 30 identical press-together pieces. The STL file for the pieces is on Thingiverse:

http://www.thingiverse.com/thing:21267

When I print these, the "tabs" come out too wide (or the space between them is too small - depends on how you look at the problem). I don't know my nozzle size (3rd hand printer), so I've played with settings for layer height, nozzle size, lowering the amount of filament fed in Slicer, etc. Still doesn't fit. The STL file results in a very small item (about 2" overall), but scaling it up doesn't solve the problem. Even scaled up to about 4.5", the parts won't really press together. Stubs continue to be too wide.

I've calibrated X, Y and Z axis's, and also the extruder. Other stuff prints pretty well.

So: Is this a case where the press-together stubs are still printed with too much filament or the wrong settings? If so, is there a setting I can adjust so the stubs aren't so wide (maybe the layers are squished down and that's causing the problem)?

Or: At a small scale, if the stubs are printing wide (squished?) by maybe .1 or .2 mm, then they won't fit. When I scale it up, the "interference" gets worse too. This leads me to think that maybe it isn't a filament or layer squishing problem. So could this be a problem with the STL file on Thingiverse instead of my printer? It looks like other people have printed this, so I tend to blame the printer. Also, the corners of the stubs are kind of rounded instead of being square, even when scaled up. But I don't know what to change to make things better.

Here are two [very] close-ups of the area where the parts are supposed to fit together. Once scaled up x1.5 and the second scaled up x2 (makes a piece about 4.5" long). To give some idea of size, on the first image, the stubs are about 2mm wide. On the second, they are about 3mm wide.

https://dl.dropboxusercontent.com/u/.../Frabjous2.JPG

https://dl.dropboxusercontent.com/u/.../Frabjous3.JPG