It appears that the custom gobos aren't working - at least not on my machine. Brightness changes occur when flipping through some values, but the gobos don't show in 3DView. I tried with 6.26, 6.27 and the latest Zip file and the symptoms are all the same. They were working perfectly on my end previously.
I checked and the files are still there and the devices have the correct files selected. My 128x128 PNG files are still located in c:\program files\showxpress\3Dview\gobos\OK_for_3Dview and the 32x32 PNG files are located in c:\program files\showxpress\icons\gobo\ok_for_3DView.
The symptoms are the same for all different kinds of moving heads that can display gobos (I have 5 types including 3 personality files that haven't changed in a long time). Are gobos working in 3DView for you?
Follow-Up on 4 June 2011: As a follow-up to my earlier post - the problem I described above may have something to do with the relative brightness of the beam in 3DView or the angle you are looking at the resulting light beams in 3DView when the fixture is displaying a gobo. As I rotate around the stage in 3DView, I can sometimes see some of the beam - but it is very dim from most angles. I am seeing similar view angle issues with some other non-gobo devices as well.