Maybe it's just me, but I can't, for the life of me, get any tape file to load into any MESS Spectrum driver. Mounting it works without any errors, although it takes a while if it's not zipped, then using the Tape Loader option on boot (or LOAD"" on the 48k) results in nothing happening. The tape counter does not appear. Stopping, then selecting play doesn't do anything.
I have tested a TZX file, a TAP file, and a converted WAV file, all do the same. The TZX and TAP files work fine in Spectaculator, so those should be fine. Cassettes work in the CPC driver (WAV files only supported), so the MESS cassette system works.
I have tested this in the current SVN and also MESS 0.108 (the version .tap/.tzx support was added).
I figured I'd post here first, in case there's some silly error I'm making, but if not, then I'll post it to Bugzilla.