I can confirm the bug with instant preview not working, where lyx leaves the following error message:  "failed: gs 0lyxpreview.ps". I have a candidate solution/workaround, see below.

Note however that the ps file LyX created in /tmp was fine in my case.

As suggested in http://archive.netbsd.se/?ml=lyx-devel&a=2007-05&t=4342060 I have installed the package dvipng which removes the "failed: gs 0lyxpreview.ps" error message. However, instant preview is still broken. I now have on the command line the following:

dvipng warning: Bad resolution (-D) parameter, ignored dvipng warning: at (75,15) unimplemented \special{ps: currentpoint currentpoint translate 0.07472 0.11023 scale neg exch neg exch translate} dvipng warning: at (91,15) unimplemented \special{ps: gsave currentpoint currentpoint translate 90 neg rotate neg exch neg exch translate} dvipng warning: at (233,15) unimplemented \special{ps: currentpoint grestore moveto} dvipng warning: at (75,15) unimplemented \special{ps: currentpoint currentpoint translate 1 0.07472 div 1 0.11023 div scale neg exch neg exch translate} dvipng warning: at (102,15) unimplemented \special{ps: currentpoint currentpoint translate 0.07472 0.11023 scale neg exch neg exch translate} dvipng warning: at (119,15) unimplemented \special{ps: gsave currentpoint currentpoint translate 90 neg rotate neg exch neg exch translate} dvipng warning: at (260,15) unimplemented \special{ps: currentpoint grestore moveto} dvipng warning: at (102,15) unimplemented \special{ps: currentpoint currentpoint translate 1 0.07472 div 1 0.11023 div scale neg exch neg exch translate} 

Ok, that was with hardy's dvipng. I installed the latest dvipng from http://download.savannah.gnu.org/releases/dvipng/ and LyX now gives me:

dvipng warning: Bad resolution (-D) parameter, ignored GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1
GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1
GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1
GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1
GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1
GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1
GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1
GPL Ghostscript 8.61: Unrecoverable error, exit code 1
dvipng warning: No GhostScript pngalpha output, cannot render raw PostScript GPL Ghostscript 8.61: Unrecoverable error, exit code 1

so it still seemed to be coming from gs.

Then I changed "document > parameters > document class > postcript driver" to Dvips and I then could have some instant preview working: there still are errors from Ghostscript when loading file, but instant preview works once you start scrolling.

My guess is:

- Try changing the "postscript driver" parameter to dvips
if it dosn't work then:
- Also Install dvipng from the repos
and if it still doesn't work
- install the latest dvipng from source

I also tried to install latest gs (8.62) but I'm not sure whether it had an impact. (Same errors but with "Ghostscript 8.62" replacing "Ghostscript 8.61")

Please report your solution if anything of the above solved your issue.

Hope it will solve your problem.