Havings problems running bills. Message below pops up.

Run Bill Checks
from 2013-04-01 00:00:00.000 to 2013-05-01 00:00:00.000
Checking 2 Meter Accounts...
Checking Meter Account 1/2: Jadwat Whs - Main Incommer - Elster A1700 no. 71501931 (2004)...
Default Tariff Ethekweni ITOU is not valid at this time. Cannot Run Bill for this Meter Account. Make sure you have Tariff Periods to cover the billing period and that your tariff is valid.
Checking Meter Account 2/2: Seaboard (Main Incommer) (1973)...
Default Tariff Ethekweni ITOU is not valid at this time. Cannot Run Bill for this Meter Account. Make sure you have Tariff Periods to cover the billing period and that your tariff is valid.
0 Meter Accounts are valid.
Cannot run Bill.

It seems like your tariff Ethekweni ITOU has reached the end of it's valid period.
Every tarriff has new rates for each year period.
When you reach the end of the tariff year period, you need to enter the new rates for the next year period before you can continue using that tariff in a bill.
To see the tariff's periods, select the tariff in the overview screen, and click on Edit->Tariff Periods.
If you see that the tariff is past it's periods, please get the new tariff rates from your local authority (usually its on their website) and add the next year period under Edit->Tariff Periods.
Then enter the new rates under Edit->Tariff Rates.
And finally validate the tariff under Tools->Check Tariff Validity.
Then you can run your bill again.