Please attached tng.log file as discussed telephonically.
We suggest using the 'Asterisk CSV File Import' option.
The format of the CSV required is the cdr-custom. Asterisk has two options cdr-custom and master, both writes out a file named master.csv. Be sure to use the file in the cdr-custom folder. For TNG configuration with Asterisk, please refer to forum post:
TNG and Asterisk: Suggested setup