This bug has been reported on Ubuntu Launchpad as:
https://bugs.launchpad.net/bugs/603159

Thunar crashed with SIGSEGV in thunar_vfs_job_source_dispatch()

DistroRelease: Ubuntu 10.04

Package: thunar 1.0.1-3ubuntu1

Uname: Linux 2.6.32-23-generic i686
Architecture: i386

ExecutablePath: /usr/bin/Thunar
ProcCmdline: Thunar --daemon

SegvAnalysis:
 Segfault happened at: 0x82b426 <thunar_vfs_job_source_dispatch+198>: mov (%esi),%edx
 PC (0x0082b426) ok
 source "(%esi)" (0x00000000) not located in a known VMA region (needed readable region)!
 destination "%edx" ok

SegvReason: reading NULL VMA
Signal: 11

StacktraceTop:
 thunar_vfs_job_source_dispatch (source=0x94fd380, callback=0,
 IA__g_main_context_dispatch (context=0x93329e8)
 g_main_context_iterate (context=0x93329e8,
 IA__g_main_loop_run (loop=0x930e7e0)
 IA__gtk_main ()

Stacktrace available:
http://launchpadlibrarian.net/51574505/Stacktrace.txt

XsessionErrors.txt log file:
http://launchpadlibrarian.net/51573884/XsessionErrors.txt