Producer "Save As" not working properly

I am using Sonar 8 Producer. A friend sent me a 5-track song to add my bass part to (4 audio, 1 MIDI). Since I didn't have all of his instrumentation, I inserted a MIDI synth and copied the MIDI track for track 1 to track 6, then deleted the empty Track 1. It renamed the tracks to 1 - 5.
 
I added an audio track, track 6, and put my bass part on.
 
When I go to "save as" and save it as a .CWB file, and open up the new saved .CWB file to play it, Sonar has replaced my bass track (6) with parts of track 1 and 2.
 
I saved a song to a .CWB file previously and it worked fine.
 
Any ideas anyone? Buler? Buler?
 
Rick

Have it saved as a .cwp, no problems there.
Yes after saving as a .cwb it plays fine, everything is okay. The problem occurs only after I close the project and reopen the .cwb. It's messed up.

Okay, then what's the best format to save in when you're going to put it in Dropbox to share with your guitarist? Is Dropbox the best and fastest way to share projects? BYW, he has Sonar 7.

Another thing is I was going to say there's no reason to move the midi tracks around. 
If you both don't have the same drum synth then simply insert whatever synth you have and point the midi tracks output to the new synth. You friend just changes it back later when he gets the file back from you. 
 
Steve, wouldn't zipping a WAVE file be the same as turning it into an MP3? I'm just wondering how Zip conversion works. Like if it would lower the quality of the project? After all Sonar is working in 32 bit wave files, a pretty high rate. 
 
I know one way to share files over the internet and keep the file size small is to create a "save as" version of a project that is striped down to basics. If your just adding Bass you only need a rough mix with an airtight arrangement. Because the drums are possibly midi this allows a bass player to turn up the Kick drum etc. 
 
The original version is kept as is. 
A new version is made using as much MIDI as possible. 
Un-needed audio tracks are left out. 
Then the few that are required are mixed to a stereo track. 
So just the CWP which contains midi data and one stereo track is uploaded. 
This project file would be not be that big.  
The second person uses this to add their parts and only has to send back with MIDI and the new tracks. The new tracks are easily dropped into the original project. 

Cool. thanks for clarification