using the dev build i've got and also the 0.6.8.5 version i couldn't get it to fail playback on either of those two.
i know there's some quirks with the title's reverting when viewing the file information (alt+3) with spc (and a few other formats). the issue where it only shows the track instead of a title, i can only get if i do a select all and then a read all information on selection action (ctrl+alt+e), other than that i'm a bit confused over what's going on.
i'll have to add some more debug info to the dll and give you a build to see if it shows up any errors. btw, what version of winamp are you using? (might be a version incompatability in some code somewhere)
The problem where they don't play only happens if I try opening another RAR file while one is already playing. If I press stop then open it, it works. But then there's still the issue of titles not appearing.
I'm using Winamp 5.35 - not sure I can select all / read all information. I guess that's in a later version of winamp? Ctrl+alt+e doesn't work at least.
edit: getting the wrapper to work RSNs/last FM seems like all this would be made academic anyway, because that's really the only problem I have with RSN currently. I'm only using in_zip as there's no other choice.
just had a thought with the rar playing and starting a new one issue... might be from the AV scanner you've got installed (if there is one). other than that i'm baffled.
modding the wrapper to support rsn files isn't such a simple thing and really when i've got code in place to do this through in_zip (which is the main project) it's more sensible to fix the issue(s) in that (is how i see it).
i'll have a chat with you on irc about this at some point in the next few days if that's ok (alas i've got to do real work and my winamp client work before i get a chance to work on my plugins)
also the only AV scanner I have installed is AVG Free. could be that... I'll try disabling it and see what happens sometime.
i'm also wondering if there are any solutions for PSF and GSF too. those are the only others that don't work (that one may expect to work) as far as I can tell.