heey paul!, well, I've tried in Mupen64plus 1.2, 1.3 and last version disabling auto frameskip and here are the results:
1.2: In this version game starts ok, but when I enter to the castle screen turns black, the sound still emulating and I can hear mario steps if I use the analog stick, but screen not shows nothing.
1.3: In this version game screen freezes when I push start on the face presentation screen (screen turns white)
1.4: In this version occurs the same thing than 1.3 version
Well... I want to tell you something else, in 1.4 version resume option never shows, I've played mario kart, mario 64, star fox and all star tennis 99, I have the "auto save" option enabled, I saved all the games even quick save in 0 slot, but option still without appear