Zero balances

[Julian]

Hi,
    I have installed Gnucash version 2.2.9 and it looks like a great program.  The problem I have is that I cannot get any transactions to show in the Assets or Income Accounts. I have set up my customers, compiled and posted their Invoices, then processed their payments, but the balances of the A/Receivable and the Income accounts are always Zero. There is no sign of the customers sales activity on any reports.  Expenses totals are working OK, but I can't fathom what I'm doing wrong with the invoicing. I've set up two different companies, but the problem is the same- all balances are zero.  I have also spent over 12 hours going over the Help/Manuals etc.  Hope you can offer some suggestions.
Cheers from Australia 
Julian Hall.