I've taken DMK73's script a little further. You will need to edit at the top tmdir to be the directory to your Time Machine backup. When run, this will make sure that directory exists first then will do the same modifications. I've added the -v flag to the chflags command so it shows what files are being modified. All output is written to a file in /tmp and then at the end it displays the output without any of the "no such file or directory" messages.
#!/bin/bash
# This script fixes an issue with the /.MobileBackups.trash folder that is created by CrashPlan
# Most of the script comes from this thread: https://discussions.apple.com/thread/5750388?start=15&tstart=0
tm_dir="/Volumes/Time Machine/Backups.backupdb/mikes-macbookpro"
tmpout="/tmp/fix_MobileBackupsTrash.tmp"
if [ ! -d "$tm_dir" ]
then
echo "Time Machine directory is not found! Fix the script"
exit 1
fi
cd "$tm_dir"
echo > $tmpout 2>&1
echo "----------------------------------------" >> $tmpout 2>&1
echo "Starting on $(date)" >> $tmpout 2>&1
echo "----------------------------------------" >> $tmpout 2>&1
echo >> $tmpout 2>&1
# Unlock all local expired backup copies of CrashPlan
[ -f /.MobileBackups.trash ] && sudo find /.MobileBackups.trash -flags +schg -exec chflags -fv noschg {} \; >> $tmpout 2>&1
# Unlock all backup copies of CrashPlan
# Need to run from Time Machine machine directory (e.g. /Volumes/MyExternalHD/Backups.backupdb/MyMac/)
find . -maxdepth 1 -type d -exec sudo /System/Library/Extensions/TMSafetyNet.kext/Contents/Helpers/bypass chflags -fv noschg "{}"/Macintosh\ HD/Applications/CrashPlan.app \; >> $tmpout 2>&1
# Unlock CrashPlan application
sudo chflags -fv noschg /Applications/CrashPlan.app >> $tmpout 2>&1
# Or exclude CrashPlan from backups
#sudo tmutil addexclusion /Applications/CrashPlan.app >> $tmpout 2>&1
echo >> $tmpout 2>&1
echo "-----------------------------------------" >> $tmpout 2>&1
echo "Completed on $(date)" >> $tmpout 2>&1
echo "-----------------------------------------" >> $tmpout 2>&1
echo >> $tmpout 2>&1
grep -v "CrashPlan.app: No such file or directory" $tmpout