I/O Error in Security Administrator

I would keep on trying until it's right, meaning, keep on trying to add it until you get no message.
Yes, there are bugs (really??!?!) in 9.0.1.5 version in several places in several modules. This type of thing I'm not surprised of. I would search for patches to resolve this type of issue.

If I try to continue after I see this error, and I create a rule using a field from the form (e.g. Line-FC)
I get the following error when I try to store the rule I get the following error:
rule evaluation: form.LINE_FC is not in the scope

There seems to be a fix for this, but is it also possible that there is a disconnect somewhere that rebooting the whole system might take care of?

You could possibly try to stop and restart security (only)... Make sure you know how to do this properly BEFORE you try to do this.
But if you want to do a clean recycle of your system, you may have to do a recycle of websphere, and the environment. I don't know what your platform is (Unix or windows), and I've been able to stop lase by itself with no problems; but other systems I've had to recycle everything if I wanted to stop lase - this applies more so to windows environments.

Has your rule ever worked? Do you have a similar rule somewhere else that does work?

Platform is UNIX.

These rules used to work before we upgraded to 9.0.1.5 and added some patches.

Our development box is on 9.0.1.5.174 and does not have this issue. Production is on 9.0.1.5.411