firefox wont start

[rfjones]

firefox 2.0 on Linux 2.6.17-1.2157_FC5
runs ok for awhile after install, then refuses to start from menu icon
start from cmdline runs with  with error message below
sometimes reinstall fixes this behaviour (runs from desktop icon)
sometimes only runs from cmdline with error message
TIA
rfjones
which: no wxdfast in
(/usr/jdk1/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/X11R6/bin:/usr/jdk1/jre/bin:/usr/local/ant/bin:/var/lib/pgsql/bin:/opt/openoffice.org2.1_sdk/linux/bin:/usr/local/Acrobat5/bin)
which: no kget in
(/usr/jdk1/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/X11R6/bin:/usr/jdk1/jre/bin:/usr/local/ant/bin:/var/lib/pgsql/bin:/opt/openoffice.org2.1_sdk/linux/bin:/usr/local/Acrobat5/bin)
which: no gwget in
(/usr/jdk1/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/X11R6/bin:/usr/jdk1/jre/bin:/usr/local/ant/bin:/var/lib/pgsql/bin:/opt/openoffice.org2.1_sdk/linux/bin:/usr/local/Acrobat5/bin)
which: no d4x in
(/usr/jdk1/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/X11R6/bin:/usr/jdk1/jre/bin:/usr/local/ant/bin:/var/lib/pgsql/bin:/opt/openoffice.org2.1_sdk/linux/bin:/usr/local/Acrobat5/bin)
which: no nt in
(/usr/jdk1/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/X11R6/bin:/usr/jdk1/jre/bin:/usr/local/ant/bin:/var/lib/pgsql/bin:/opt/openoffice.org2.1_sdk/linux/bin:/usr/local/Acrobat5/bin)
Cutting log (size: 100571, max: 100000)