I don't recall the version
It may have been pcAnywhere 10 that gave the rather superb error message:

"Error loading error message"

Good work Symantec, your work is done here.
(zebby wasting irony here on, Wed 30 Sep 2009, 13:44, 5 replies)

LANDesk Console
I had an equally absurd error message when trying to search for a call that was logged on our help desk package, it read:

'Exception has been thrown by the target of an invocation'

What the fuck?? Couldn't it just say 'the search failed' or something simple like that?!
( Fat Fred too weird to live, too rare to die, Wed 30 Sep 2009, 14:05, closed)

A portal...
...I use at work throws up the error message "Your session timed out because you were idle for too long", if you don't use it for more than 20 minutes. How do they know what I [don't] get up to at work?
(SonoraAeroClub "OH SWEET HELEN OF BALLS!", Wed 30 Sep 2009, 14:17, closed)

well, you were talking for too long
while there was science to do
(The Incredible Sulk Finally remembered his password on, Wed 30 Sep 2009, 21:47, closed)

We have a rather interesting message on our Firewall at work...
"Authentication Failed: Login Succeeded"

There was also a rather amusing .jpeg that I saw on teh interwebs a while ago with the following Vista error message:

"Error - the operation completed successfully"
(Cow_Tipping_Samurai, Wed 30 Sep 2009, 15:10, closed)

Morse
I copied and pasted your morse code into a translator and did a lol all over myself.
(Patrice Ici Reticulating Splines, Wed 30 Sep 2009, 21:30, closed)