7250 switches off+onn when looking thru ringtone gallery

I used the Nokia PC suite to copy a standard .OTA ringtone into the Tones folder under "Gallery". It seems it only likes .MID files in here, as when i scroll through, as soon as I get to the copied one, the phone switches itself off and on. I used the Nokia phone browser to delete it, but it's still there. If i refresh it on the computer, it does not get displayed, but it is still actually on the phone.
I also have a trial version of Oxygen Phone Manager 2.1. The ringtone appears here, but if i delete it, i dont get the option to write the changes back to phone (i dont know if this would work anyway)

Can anyone give me a clue as to how to delete this ringtone from the phone?

Thanks!