Well, your description is rather vague, so hard to guess the cause.
May be the utility you are using is not compiled for the system you are running it on.
Have you ringtone acceptable length ? If I remember correctly:
- Minimum ring size — 240 samples
- Maximum ring size — 16080 samples
- Number of samples in the ring must be evenly divisible by 240
- Ring should start and end at the zero crossing
You should narrow the issue cause. Make sure your file is correct format and length. Turn on syslog&debug and catch them. Capture the communication between utility and phone.
It will help us to analyze the cause.