Handling bond purchases and sales

[subscribe307 at verizon.net]

I am trying to set up an automatic sale of a bond when it matures.  When 
I enter all the data in the scheduled transaction and check the box to 
create automatically I get the dialog box saying "Scheduled Transactions 
with variables cannot be automatically created" when the transaction is 
completed with the OK.  I don't understand what is considered a variable 
or if there is a way around this to have this transaction created 
automatically.
The second question I have is what to use as a symbol/abbreviation in 
order to receive updated quotes for a bond in the US in the New Security 
information when setting up the account under the Security/currency entry.