I am having a strange problem with BIAB

I have a few songs that I play one after the other like in a set, normally I mute the Melody and I play along with my guitar... when I want to play the next song, I just double-click on another file in my folder and the next song comes up on BIAB, etc... This way, I can play all the songs (say 10 of them in a set) one after the other with no problem. [The songs usually have Realdrums on the Drum Track, and one or two RealTracks, say for Piano and Soloist tracks, etc...)

There are a couple of songs that if I start with that song, I get a dialogue box that pops up and asks me if

"OK to Change Melody to Straight Feel?"

No matter what I choose (i.e. YES, NO, CANCEL) BIAB drops the RealTracks and just plays the MIDI versions... (i.e. the Green lettering on the track names turns to yellow too.)

Now it's interesting that if the same song is played after another song (without closing the BIAB) everything works fine....

A bit unreleated (but as annoying), once in a while, when I double-click on the next song on my list of songs in the folder, a SECOND BIAB session opens up... Although both BIAB applications are still operatonal (i.e. not crashed, or not Not-Responding), I am forced to MUTE the melody part AGAIN, and also turn to the Notes page so I can follow the Tabs/notes for the melody track I play with my guitar...

Any Ideas how to solve this?

2008 Gibson ES-339 Custom & 2010 Les Paul Traditional. Fender SCXD Amp
BIAB/RB 2015 UltraPAK + Ketron SD2
Windows 7/64 Intel i5 3550 PC, Tascam USB144MKII
Behringer X1204 Mixer
Bose Companion 3 and/or L1 II w/T1 + SM58 MIC