Here’s a patch file

— svn-growlnotify.sh 2010-05-04 15:15:22.000000000 -0700
+++ /Users/sean/bin/svn-growlnotify.sh 2012-01-26 16:43:35.000000000 -0800
@@ -10,7 +10,6 @@
# Default settings
SVN_ROOT=”"
LOG_URL=”"
-REV_FILE=”$HOME/.svn-growlnotify.version”
MAX_REVS=”5″
GROWLNOTIFY=”/usr/local/bin/growlnotify”

@@ -24,6 +23,9 @@
g) GROWLNOTIFY=$OPTARG;;
esac
done
+REV_FILE=”$HOME/.svn-growlnotify/$(basename $SVN_ROOT)”
+
+test -d $HOME/.svn-growlnotify || mkdir -p $HOME/.svn-growlnotify

if [ "$SVN_ROOT" = "" ]; then
echo “Usage: $0 -s [-l LOG_URL] [-r REV_FILE] [-m MAX_REVS] [-g GROWLNOTIFY]”

I also converted your cronjobs to a launchd job. Mine is set to 120 seconds instead of 60.

Label
repository name
ProgramArguments

/path/to/svn-growlnotify.sh
-s
http://your.repository.ur/l
1>/dev/null
2>&1

StartInterval
120

I named the file svn.repository.plist, and put it in ~/Library/LaunchAgents
then I ran launchctl load svn.repository.plist

Sean