Ya know, I was thinking, did I give them all the info needed to figure out the problem, and I thought, yes I did.
Well, no I didn't.
The way I load/mount a Truecrypt container is thru association. I have an extension associated with truecrypt containers so all I have to do is double click on them in Dolphin. This brings up the truecrypt password dialog window, I enter the password and then it mounts the container in /media with a folder name of truecrypt1 etc.
Well, if I load a container this way and then try to dismount it, I get that nasty error and I have to sysreq-REISUB to reboot the system.
*BUT*, if I load a container thru the Truecrypt gui, then I can dismount the container without problem. Yaaaaa!
I do like the first way though, as it is more convenient.