Please note that Oracle's acquisition of AppForge's intellectual property did not include the purchase of the company as a whole, or the purchase of other AppForge assets including its customer contracts. Accordingly, Oracle does not plan to sell or provide support for former AppForge products going forward.
It looks like appforge is no longer being developed/supported (it stopped in April 2007). You might be able to find a copy somewhere, but as it is no longer being supported (and hasn't been for 3 years) it may be in your best interest to start looking for some different software.
What is it specifically you need this for?