Running the following script:

<JiraJelly xmlns:jira="jelly:com.atlassian.jira.jelly.JiraTagLib">
<jira:Login username="bob" password="password">
<jira:AttachFile key="ABC-218"
filepath="/home/sccs/build/build_SUP_000093.TEST.20050928090900.log"
option="override"/>
<jira:AddComment comment="Test"
issue-key="ABC-218" commentLevel="jira-users"/>
</jira:Login>
</JiraJelly>

will fail with the following message in the logs:

2005-10-04 10:11:05,675 [webwork.dispatcher.ServletDispatcher] Unable to find 'webwork.multipart.saveDir' property setting. Defaulting to javax.servlet.context.tempdir
2005-10-04 10:12:16,475 ERROR [web.action.util.JellyRunner] Could not run script.
org.apache.commons.jelly.JellyTagException: null:5:0: <jira:AttachFile> Unable to make temporary copy of file.

and rather confusingly, the 'jelly is disabled' message in the browser:

As a security precaution, the Jelly Runner on this installation is currently disabled. To enable Jelly support, please start JIRA with "-Djira.jelly.on=true". For more information see the Jelly Documentation.

It looks like there is some fault in the Jelly runner logic which is throwing up the wrong error page.