svn propset svn:log wont work for me.

I am a new svn administrator and also the primary user. I'm stuck on an issue which I can't resolve and would like some help.

On a server I have svn running which I access via apache. I'm at revision 220 on this particular repository so it seems to be mostly working correctly. I flubbed the revision log on a check in (I like to associate svn revisions with bug IDs) and want to correct this, but running propset or propedit never succeed.

A bit of information about the server side set-up ...

[apache_at_X hooks]$ id
uid=48(apache) gid=48(apache) ...

apache_at_X hooks]$ pwd
Y/hooks

[apache_at_X hooks]$ ls -l pre-revprop-change
-rwxr-xr-x. 1 apache apache 2890 Sep 2 08:39 pre-revprop-change << so I seem to have a valid hook

[apache_at_irvine hooks]$ tail -14 pre-revprop-change
REPOS="$1"
REV="$2"
USER="$3"
PROPNAME="$4"
ACTION="$5"

echo "running" >/tmp/tmp << a test to see if the hook is run
exit 0; << always succeed (as a debug aid)

if [ "$ACTION" = "M" -a "$PROPNAME" = "svn:log" ]; then exit 0; fi
if [ "$ACTION" = "A" -a "$PROPNAME" = "svn:author" ]; then exit 0; fi

echo "Changing revision properties other than svn:log is prohibited" >&2
exit 1

I placed the two lines 'echo "running" >/tmp/tmp' and 'exit 0;' in the file as a debugging aid.

[apache_at_X hooks]$ ls /tmp/tmp
ls: cannot access /tmp/tmp: No such file or directory << I believe that running the hook would create this file

So whatever is going on I don't think the hook is even being run.

---
On my work station I have the following output:
[dgb_at_Z c15]$ svn log -r220                                                                       << so I'm in a valid working directory and have repo access
------------------------------------------------------------------------
r220 | dgb | 2011-09-01 16:13:26 -0700 (Thu, 01 Sep 2011) | 1 line
reslove bug 189
------------------------------------------------------------------------
[dgb_at_Z c15]$ svn propset svn:log "a new comment" --revprop -r220
svn: DAV request failed; it's possible that the repository's pre-revprop-change hook either failed or is non-existent
svn: At least one property change failed; repository is unchanged
svn: Error setting property 'log': 
Revprop change blocked by pre-revprop-change hook (exit code 255) with no output.               << this is what I'd like to work
[dgb_at_Z c15]$ date
Fri Sep  2 10:04:15 PDT 2011                                                                                             << this is when the failure occurred 
Back on the server
[root_at_X httpd]# pwd
/var/log/httpd
[root_at_X httpd]# tail -4 error_log
[Fri Sep 02 08:51:32 2011] [error] [client 192.168.1.138] Revprop change blocked by pre-revprop-change hook (exit code 255) with no output.  [500, #165001]
[Fri Sep 02 08:51:32 2011] [error] [client 192.168.1.138] Could not execute PROPPATCH.  [500, #206]
[Fri Sep 02 08:51:32 2011] [error] [client 192.168.1.138] Revprop change blocked by pre-revprop-change hook (exit code 255) with no output.  [500, #165001]
                                                                                                                                        << there are errors, but they are old
                                                                                                                                        << (whatever that means)
[root_at_X httpd]# date
Fri Sep  2 10:00:13 PDT 2011
[root_at_X httpd]# tail -4 svn_logfile 
[02/Sep/2011:09:25:04 -0700] dgb rev-proplist r220
[02/Sep/2011:09:25:38 -0700] dgb change-rev-prop r220 svn:log
[02/Sep/2011:09:54:44 -0700] dgb log (/trunk) r220:220 revprops=(svn:author svn:date svn:log)
[02/Sep/2011:09:55:27 -0700] dgb change-rev-prop r220 svn:log                                           << svn is aware of the request
The propset command fails with or without the URL appended.  In the error_log there are indications of previous failures, but I no longer get those even when I remove the pre-revprop-change file.  I've tried svn propedit remotely and locally.  Remotely the command doesn't load the the current log message and fails.  Locally the command at least loads the current comment into the editor, but when I close the editor the update fails with the same error messages as it does remotely.
[root_at_X httpd]#svn --version
svn, version 1.6.13 (r1002816)
   compiled Oct  5 2010, 09:54:56
Copyright (C) 2000-2009 CollabNet.
Subversion is open source software, see http://subversion.tigris.org/
This product includes software developed by CollabNet (http://www.Collab.Net/).
The following repository access (RA) modules are available:
* ra_neon : Module for accessing a repository via WebDAV protocol using Neon.
  - handles 'http' scheme
  - handles 'https' scheme
* ra_svn : Module for accessing a repository using the svn network protocol.
  - with Cyrus SASL authentication
  - handles 'svn' scheme
* ra_local : Module for accessing a repository on local disk.
  - handles 'file' scheme
I'd appreciate any help in  gettin this working.  Thank you so much for reading.
Best Regards
Douglas