This issue is caused by a mismatched Samplerate, Bitrate, or Channel Type between your stream and your intro file. An intro file MUST be the EXACT same Samplerate, Bitrate, and Channel Type (stereo/mono) as your audio stream.  If it is not, your music will sound garbled and will not play correctly.

Please ensure that you have double and triple-checked this before submitting a support ticket.