Your comments

Great news. Can't wait for the next release. If I knew the problem was launching it from Dropbox folder (/sdcard/Android/data/ instead of, for example, /sdcard/Download, I would have been fine with simply making a copy of my playlist there. I tested that and it works just fine. Obviously launching it directly from my Dropbox folder will be even better!

BTW, looks like you might have a problem with file names with spaces. "Radio Stations.m3u" fails with "Fail to connect" but "Radio.m3u" works. Does not bother me, just an FYI.

PS. Sorry for being a bit cranky. I appreciate getting back to me.
Well, you must admit I have been patient (a month!). For me the ability to play M3U playlist is a must. Since I paid for this app I would expect a bit more prompt support. Perhaps it is time for a bad review. It might be futile in a grand scheme of things, but it will make me feel better and might stop others from wasting their money.