Description of problem:
If a system is subscribed to a base software channel, and user goes to $system > Software > Software Channels, this channel is highlighted by default in the "Base Software Channel" listbox.

However, if system is not subscribed to a base channel, nothing is highlighted.  Hitting the "Confirm" button in this state results in ISE.

Version-Release number of selected component (if applicable):
Satellite-5.3.0-RHEL5-re20090306.2-i386.iso

How reproducible:
Every time


Steps to Reproduce:

Prerequisite -
* Assure you have one or more standard base channels synced
* Assure you have one or more systems registered 

1.  Navigate to $system > Software > Software Channels
2.  In the "Base Software Channel" listbox, note that your current base channel /is/ highlighted.
3.  select "(none, disable service)" and hit "Confirm"
4.  Click "Modify Base Software Channel" on ensuing page.
5.  After being returned to the "Software Channel" page, observe the "Base Software Channel" listbox.
6.  Click the "Confirm" button.

Actual results:

ISE

Expected results:

No ISE, but this is probably occurring due to a null value being submitted.  

The real issue here is that "(none, disable service)" should probably be highlighted by default if the system indeed has no base channel.  This would avoid the possibility of submitting a null value.

Additional info:

Note that this seems to be the only way I can find to actually "Confirm" without /something/ being selected.  That's why it's more important to simply assure something is always selected, versus trying to debug an ISE which is probably simply due to a null submit.