Bluetooth, FExplore & Nokia 6600 query

I wonder if you can help me.

I have recently installed FExplore on my Nokia 6600 and I wonder if you can
help me with a problem I have.

I tried to send a ringtone via Bluetooth to another phone. I loaded
FExplore found the ringtone, selected options, then send, then via
Bluetooth. Then it will list the Bluetooth devices available and once I
have selected the device it starts sending.

However, on some ringtones I do not get the option to select a Bluetooth
device it just doesn't display it and it doesn't send the ringtone.

Why can I send some ringtones but not others?
Is there something I can do to enable me to send the ringtones that at
present I cannot send?

I hope you understand what I mean and I hope you are able to help me.

I appreciate any help or information given.

Thanks!