Problem with Garageband volume settings

I'm using Garageband to mix music for a four hour party. I just want to fade the songs in and out so that the music flows continuously. So each song is a different track and I've been adjusting the volume for each individual track. For example, at the end of one song, I bring the volume down while the next song is comig in. Which works fine for 20 minutes (about 500 measures), but if I try to adjust the volume of a track after that, I'm unable to move the points on the volume bar. It's like suddenly I no longer have that function. Does anyone have any idea what's going on?

 

Thanks for the suggestions. Even after extending the recording limit though, I still wasn't able to adjust the volume settings past about 35 minutes. What I ended up doing was several 30 minute mixes, which worked ok.

The link you sent Flowbee said the 2.0 version had fixed this problem. I tried to install it but "An eligible GarageBand application was not found in /Applications." I have Garageband and it's in Applications, so I'm not sure what the problem is.