tomboy crashes with sharing violation

[ERROR 10:35:24.818] Exception while saving note: System.IO.IOException: Sharing violation on path /home/hloeung/.local/share/tomboy/1ed2e02c-a46b-4ac0-928b-442979abd147.note.tmp
  at System.IO.FileStream..ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean anonymous, FileOptions options) [0x00000] in <filename unknown>:0
  at System.IO.FileStream..ctor (System.String path, FileMode mode, FileAccess access, FileShare share) [0x00000] in <filename unknown>:0
  at (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare)
  at System.IO.StreamWriter..ctor (System.String path, Boolean append, System.Text.Encoding encoding, Int32 bufferSize) [0x00000] in <filename unknown>:0
  at System.IO.StreamWriter..ctor (System.String path, Boolean append, System.Text.Encoding encoding) [0x00000] in <filename unknown>:0
  at (wrapper remoting-invoke-with-check) System.IO.StreamWriter:.ctor (string,bool,System.Text.Encoding)
  at System.Xml.XmlWriter.Create (System.String file, System.Xml.XmlWriterSettings settings) [0x00000] in <filename unknown>:0
  at Tomboy.NoteArchiver.WriteFile (System.String write_file, Tomboy.NoteData note) [0x00000] in <filename unknown>:0
  at Tomboy.NoteArchiver.Write (System.String write_file, Tomboy.NoteData note) [0x00000] in <filename unknown>:0
  at Tomboy.Note.Save () [0x00000] in <filename unknown>:0
Stacktrace:

  at (wrapper managed-to-native) Gtk.Application.gtk_main () <0xffffffff>
  at Gtk.Application.Run () <0x0000b>
  at Tomboy.GnomeApplication.StartMainLoop () <0x0000b>
  at Tomboy.Application.StartMainLoop () <0x00022>
  at Tomboy.Tomboy.StartTrayIcon () <0x00053>
  at Tomboy.Tomboy.Main (string[]) <0x0031b>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object (object,intptr,intptr,intptr) <0xffffffff>

Native stacktrace:

        mono() [0x49117a]
        mono() [0x4e05ef]
        mono() [0x41b187]
        /lib/x86_64-linux-gnu/libpthread.so.0(+0x10040) [0x7f6859851040]
        /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(gdk_window_set_geometry_hints+0x4) [0x7f68550784b4]
        /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0(+0x266ea3) [0x7f6855522ea3]
        /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0(g_closure_invoke+0x154) [0x7f684f3c7ed4]
        /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0(+0x21fb4) [0x7f684f3dafb4]
        /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0(g_signal_emit_valist+0x767) [0x7f684f3e4797]
        /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0(g_signal_emit+0x82) [0x7f684f3e4962]
        /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0(+0xb8f00) [0x7f6855374f00]
        /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(+0x1dd26) [0x7f6855027d26]
        /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_context_dispatch+0x1dd) [0x7f6855bc4efd]
        /lib/x86_64-linux-gnu/libglib-2.0.so.0(+0x456f8) [0x7f6855bc56f8]
        /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_loop_run+0x162) [0x7f6855bc5c32]
        /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0(gtk_main+0xa7) [0x7f68553f0dd7]
        [0x405ee085]

Debug info from gdb:

Could not attach to process. If your uid matches the uid of the target
process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
again as the root user. For more details, see /etc/sysctl.d/10-ptrace.conf
ptrace: Operation not permitted.
No threads.

=================================================================
Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: tomboy 1.7.4-1ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-9.14-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
Architecture: amd64
Date: Fri Aug 26 10:38:48 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta amd64 (20110413)
ProcEnviron:
 LANGUAGE=en_AU:en_GB:en
 PATH=(custom, no user)
 LANG=en_AU.UTF-8
 LC_MESSAGES=en_AU.UTF-8
 SHELL=/bin/bash
SourcePackage: tomboy
UpgradeStatus: Upgraded to oneiric on 2011-08-08 (17 days ago)