When the bpmdjraw cannot be started to generate an output file, then the md5sum cannot be obtained leading to an assertion when trying to read that part. Below is an example of such an output. Debug: Started bpmdjraw ./ cd546/Electro1/Q:Duplicates/Sunday8PM/HourOfNeed[Faithless].mp3 BPMDJ-RAW arguments LOCATION = cd546/Electro1/Q:Duplicates/Sunday8PM/HourOfNeed[Faithless].mp3 RAWNAME = ./HourOfNeed[Faithless].mp3.raw EXTENSION = mp3 DECODER = 1 Information: 0. Wave written: HourOfNeed[Faithless] Debug: Started md5sum ./index/HourOfNeed[Faithless].idx | awk '{printf $1}' >sum.tmp Information: 1. Md5 sum: 8a44102539ae87b29ed6b9cf8f5725fa bpmplay: files.c++:12: long int fsize(FILE*): Assertion `f' failed.