chrisbates
I am using some 32 bit plugins and my version of X2 is 64 bit, but they work during playback, so why wouldn't they work during mixdown or export.

It's not uncommon for plugins to have trouble with offline bounce which is probably why Cakewalk Tech recommend trying real-time bounce.
 
If you're running a very small buffer, like 2ms or less, try going back to fast bounce and using a larger buffer size; If that works, you can increase bouncebuffsizemsec=0 in AUD.INI to something higher. Zero means SONAR defaults to using your real-time buffer size for offline bouncing.  Some plugs have trouble doing a fast bounce with a small buffer. I found this when Rapture had a problem bouncing at anything less than 4ms. I've had bouncebuffsizemsec set to 20 through several versions now.
 
 

PROBLEM SOLVED

Craig, Jack, George, Brundlefly, George, Shambler, and all.

Am deliriously happy to report the problem has been SOLVED!

I started breaking down the project, and simplifying whenever possible.
I deleted redundant tracks, unused takes, muted tracks, whatever.

Bounced the synth tracks to audio, and then deleted the synth tracks
.
Eliminated 32 bit plugs if I had a 64 bit one that served the purpose.

I noticed one audio guitar track that must've been corrupted, 'cause
when I muted it, it muted everything, even though the mute button only changed color in that track!
Releasing the mute button on that trick caused a big CLICK like the audio was being plugged in.
So I bounced that to another track, and deleted the original. Problem solved.

Also I ran all tracks to a sub bus for reverb, and I discovered a way louder and cleaner mix by bypassing the sub buss and routing everything directly to the master. Digitally, I don't know why that's so.

I have no trouble exporting now, and get a consistent quality every time, (as long as hit CTRL+A prior to export) so I'm just tweaking away, having a great time.

To all those who read and responded, THANK YOU! I couldn't have been lead to the answer without the help and encouragement of those who are on this forum.