You need to check out the documentation quintum provides if you want to dive into using freeradius.
http://www.quintum.com/support/xplatform/ivr_acct/Billing_Authentication_Handbook.chm
That said,
You aren’t going to see any radius information on prepaid ivrtype until you actually enter the information, after the IVR plays.
If you are getting failed tftp requests… do you have the tftp server with the proper languages files setup?