I am getting the following error on Itanium with ImageMagick 6.3.5 doing:
convert -debug All dress.pdf dress.png
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: utility.c/unknown/805/Configure
Command line: /usr/local/bin/convert {/app/ptc/windchill/lcsdocuments/dress.pdf[0]} {-debug} {All} {/app/ptc/windchill/lcsdocuments/dress.png}
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Blob convert[6414]: blob.c/unknown/2352/Blob
read 4096 magic header bytes
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Cache convert[6414]: cache.c/unknown/2141/Cache
destroy
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/lib/ImageMagick-6.3.5/config/magic.xml"
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/share/ImageMagick-6.3.5/config/magic.xml"
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/share/doc/ImageMagick-6.3.5/magic.xml"
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/share/ImageMagick-6.3.5/magic.xml"
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/home/ptc/.magick/magic.xml"
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "magic.xml"
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Exception convert[6414]: configure.c/unknown/507/Exception
unable to access configure file `magic.xml'
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Exception convert[6414]: magic.c/unknown/871/Exception
unable to access configure file `'
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Configure convert[6414]: magic.c/unknown/678/Configure
Loading magic map "built-in" ...
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Blob convert[6414]: blob.c/unknown/2352/Blob
read 4096 magic header bytes
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Cache convert[6414]: cache.c/unknown/2141/Cache
destroy
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Blob convert[6414]: blob.c/unknown/2352/Blob
read 4096 magic header bytes
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Resource convert[6414]: resource.c/unknown/418/Resource
/var/tmp/magick-a0006414
2007-10-11T16:07:27-04:00 0:01 0.000u 6.3.5 Resource convert[6414]: resource.c/unknown/859/Resource
/var/tmp/magick-a0006414
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Resource convert[6414]: resource.c/unknown/418/Resource
/var/tmp/magick-b0006414
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/lib/ImageMagick-6.3.5/config/delegates.xml"
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/share/ImageMagick-6.3.5/config/delegates.xml"
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/share/doc/ImageMagick-6.3.5/delegates.xml"
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/usr/local/share/ImageMagick-6.3.5/delegates.xml"
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "/home/ptc/.magick/delegates.xml"
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Configure convert[6414]: configure.c/unknown/482/Configure
Searching for configure file: "delegates.xml"
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Configure convert[6414]: delegate.c/unknown/1158/Configure
Loading delegate map "/usr/local/lib/ImageMagick-6.3.5/config/delegates.xml" ...
2007-10-11T16:07:27-04:00 0:01 0.010u 6.3.5 Resource convert[6414]: resource.c/unknown/418/Resource
/var/tmp/magick-c0006414
/usr/lib/hpux32/dld.so: Unsatisfied code symbol 'jpeg_resync_to_restart' in load module '/usr/local/bin/gs'.
2007-10-11T16:07:27-04:00 0:01 0.020u 6.3.5 Exception convert[6414]: utility.c/unknown/1627/Exception
`%s': %s "gs" -q -dQUIET -dSAFER -dPARANOIDSAFE -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=0 "-sDEVICE=pnmraw" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-g612x792" "-r72x72" -dFirstPage=1 -dLastPage=1 "-sOutputFile=/var/tmp/magick-c0006414" "-f/var/tmp/magick-b0006414" "-f/var/tmp/magick-a0006414"
convert: `%s': %s "gs" -q -dQUIET -dSAFER -dPARANOIDSAFE -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=0 "-sDEVICE=pnmraw" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-g612x792" "-r72x72" -dFirstPage=1 -dLastPage=1 "-sOutputFile=/var/tmp/magick-c0006414" "-f/var/tmp/magick-b0006414" "-f/var/tmp/magick-a0006414".
2007-10-11T16:07:27-04:00 0:01 0.020u 6.3.5 Resource convert[6414]: resource.c/unknown/859/Resource
/var/tmp/magick-b0006414
2007-10-11T16:07:27-04:00 0:01 0.020u 6.3.5 Resource convert[6414]: resource.c/unknown/859/Resource
/var/tmp/magick-c0006414
2007-10-11T16:07:27-04:00 0:01 0.020u 6.3.5 Resource convert[6414]: resource.c/unknown/859/Resource
/var/tmp/magick-a0006414
2007-10-11T16:07:27-04:00 0:01 0.020u 6.3.5 Exception convert[6414]: pdf.c/unknown/565/Exception
Postscript delegate failed `app/ptc/windchill/lcsdocuments/dress.pdf': No such file or directory
2007-10-11T16:07:27-04:00 0:01 0.020u 6.3.5 Exception convert[6414]: convert.c/unknown/2614/Exception
missing an image filename `/app/ptc/windchill/lcsdocuments/dress.png'
convert: Postscript delegate failed `/app/ptc/windchill/lcsdocuments/dress.pdf': No such file or directory.
convert: missing an image filename `/app/ptc/windchill/lcsdocuments/dress.png'.
LD_LIBRARY_PATH does contain /usr/local/lib as its first item. gs can load the the PDF file without any problem.