Comment 2 for bug 395489

here is a backtrace:

(gdb) bt
#0 0xb78633d7 in g_str_hash () from /usr/lib/libglib-2.0.so.0
#1 0xb78313fb in g_hash_table_lookup () from /usr/lib/libglib-2.0.so.0
#2 0xb62fbf2f in ?? ()
   from /usr/lib/nautilus/extensions-2.0/libnautilus-ubuntuone.so
#3 0xb7f44033 in nautilus_info_provider_update_file_info (provider=0x0,
    file=0x8fe51d8, update_complete=0x8fda3a0, handle=0x8ad3d20)
    at nautilus-info-provider.c:76
#4 0x080fc888 in extension_info_start (directory=0x8b2de80, file=0x8fe51d8,
    doing_io=0xbfaa26b8) at nautilus-directory-async.c:4544
#5 0x080f9250 in nautilus_directory_async_state_changed (directory=0x8b2de80)
    at nautilus-directory-async.c:4625
#6 0x080fa8f7 in link_info_done (directory=0x8b2de80, file=0x8fe51d8,
    uri=0x0, name=0x0, icon=0x0, is_launcher=0, is_foreign=0)
    at nautilus-directory-async.c:3637
#7 0x080faa14 in lacks_link_info (file=0x8fe51d8)
    at nautilus-directory-async.c:1737
#8 0x080f6504 in has_problem (directory=0x0, file=0x8b4dc30,
    problem=0x80fa990 <lacks_link_info>) at nautilus-directory-async.c:1785
#9 0x080f7d1d in request_is_satisfied (directory=0x8b2de80, file=0x8fe51d8,
    request=1) at nautilus-directory-async.c:1868
#10 0x08158f8d in vfs_file_check_if_ready (file=0x8fe51d8, file_attributes=547)
    at nautilus-vfs-file.c:87
#11 0x0811a79c in nautilus_file_check_if_ready (file=0x8fe51d8,