For the record, the prompt you have in the screen shot is exactly what I am looking for. I changed the embedded script you provided in your latest post and restarted Hazel. This is the error I am getting now in the log file.
2012-04-05 23:24:31.215 (null)[0] Screen Shot 2012-04-04 at 3.38.02 PM.png: Rule Screen Shot Rename matched.
2012-04-05 23:24:31.344 hazelworker[71531] [Error] AppleScript failed: Error executing AppleScript on file /Users/murr/Desktop/Screen Shot 2012-04-04 at 3.38.02 PM.png.
2012-04-05 23:24:31.346 hazelworker[71531] AppleScript error: {
NSLocalizedDescription = "Can\U2019t make \U00abclass posx\U00bb of \"/Library/PreferencePanes/Hazel.prefPane/Contents/Resources/Hazel.icns\" into type string.";
NSLocalizedFailureReason = "Can\U2019t make \U00abclass posx\U00bb of \"/Library/PreferencePanes/Hazel.prefPane/Contents/Resources/Hazel.icns\" into type string.";
OSAScriptErrorAppAddressKey = "<NSAppleEventDescriptor: 'null'()>";
OSAScriptErrorBriefMessageKey = "Can\U2019t make \U00abclass posx\U00bb of \"/Library/PreferencePanes/Hazel.prefPane/Contents/Resources/Hazel.icns\" into type string.";
OSAScriptErrorExpectedTypeKey = "<NSAppleEventDescriptor: 'TEXT'>";
OSAScriptErrorMessageKey = "Can\U2019t make \U00abclass posx\U00bb of \"/Library/PreferencePanes/Hazel.prefPane/Contents/Resources/Hazel.icns\" into type string.";
OSAScriptErrorNumberKey = "-1700";
OSAScriptErrorOffendingObjectKey = "<NSAppleEventDescriptor: 'obj '{ 'form':'prop', 'want':'prop', 'seld':'posx', 'from':'utxt'(\"/Library/PreferencePanes/Hazel.prefPane/Contents/Resources/Hazel.icns\") }>";
OSAScriptErrorRangeKey = "NSRange: {0, 0}";
}