Permission denied & readlink errors

[Leaw, Chern Jian]

HI,
I encountered the following errors below when using rsync version 2.5.6, with the options:
# rsync -avzo --delete /src /dest

I invoked rsync as a root user. The source and destination filesystems (both reside on the NFS disks), have been exported with root privileges. 

1) This file below does exists, however rsync complained of a "No such file or directory" error:
readlink .snapshot/hourly.5/release_area/westport/westport_BRLS05/pci_unit/celtic/r
undir2/pci_unit_celtic_minTTTT_noise_html/waveform73.html: No such file or directory

2) The file below does not exists on neither the source or destination side, but produced the error "No such file or directory" when attempting to transfer it.
send_files failed to open /pgfs2/wp17/block/eteh1/westport/pci_unit/rv/rundir/pci_unit/ice/sub_parallel_0009.log: No such file or directory
send_files failed to open /pgfs2/wp17/block/eteh1/westport/pci_unit/rv/rundir/pci_unit/ice/sub_parallel_0010.log: No such file or directory

3) When applying the delete option to remove files which do not exists on the source from the destination filesystem, it produced a "Permission denied" error.
Permission settings for all filesystems on the source and dest have been set to 755(-rwxr-xr-x):
delete_one: unlink .snapshot/hourly.1/block/kboey/kboey/westport/pci_power/power/npe/npe0_wp_gv_132/pci_unit_htmldir/25/1832.html: Permission denied
delete_one: unlink .snapshot/hourly.1/block/kboey/kboey/westport/pci_power/power/npe/npe0_wp_gv_132/pci_unit_htmldir/25/1831.html: Permission denied


4) Error below occurs upon completion of transfer. 
block/sloh1/sloh1/westport/jt/timing/rundir_xtalk2/jt_unit_celtic_minTTTT.sdf -> /pgfs2/wp08/block/sloh1/sloh1/westport/jt/celtic/rundir2/jt_unit_celtic_minTTTT.sdf
wrote 3943721362 bytes  read 743332 bytes  104211.69 bytes/sec
rsync error: some files could not be transferred (code 23) at main.c(620)
total size is 74291787146  speedup is 18.83
Sun Jul 20 04:20:09 MAL 2003

May I know how I could troubleshoot such errors mentioned above? May I know what could possibly be the root cause of the errors above? 

Thanks