Factoids plugin gets IllegalStateException in odd cases

[FauxFaux]

IRC conversation:
{{{
[14:09:20] !ask Sadiq Is there any way, through evil hacks, clever hacks, or just downright sensible option changes, that we can get Trac to use a real date format? The current one is really pissing me off, as I keep reading it wrong. :( (dd/mm/yyyy would do, but yyyy-mm-dd would be much better, or some format with a month name)
[14:09:21] Vilers: The plugin author was too lazy to trap the exception: java.lang.IllegalStateException: No match found
[14:09:22] <Choobie|> Vilers: The plugin author was too lazy to trap the exception: java.lang.IllegalStateException: No match found
[14:09:22] Vilers: OK, will ask upon next speaking. (Sent to one person.)
}}}

Exception trace:
{{{
Exception invoking method public void plugins.Factoids.Factoids.filterFactoids(org.uwcs.choob.support.events.Message,org.uwcs.choob.modules.Modules,org.uwcs.choob.support.IRCInterface) throws org.uwcs.choob.support.Choob
Exception
java.lang.IllegalStateException: No match found
at java.util.regex.Matcher.group(Matcher.java:461)
at plugins.Factoids.Factoids.filterFactoids(Factoids.java:35)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.uwcs.choob.plugins.HaxSunPluginManager$2.run(HaxSunPluginManager.java:401)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
at java.lang.Thread.run(Thread.java:595)
}}}

SVN revision: 330.

[FauxFaux]

Author: sadiq
'Fixed' by [350]. I need to figure out why that exception is thrown though. I have a feeling it's to do with the regex being off slightly.

[FauxFaux]

Author: bucko
The issue here was case sensitivity. Filters are MATCHED case sensitive, but are not, by default, COMPILED tht way.

[FauxFaux]

Ticket imported from Trac:
http://trac.uwcs.co.uk/choob/ticket/44