recurring and annoying crash problem

so, this is occurring in a single project - ie, hasn't occurred in other projects.

I have 33 tracks and about 8 busses.   very few plugins are employed.   if i try to add another buss, it crashes and i get apphang error.

I love using sonar and i've been a loyal user since the very early days but this is getting ridiculous.  I've battled with this apphang error crash even before this occurrence but i thought i solved it.  

this time, i try all the stops to avoid - even disabling or removing (suspiciously offending) plugs   I also cleaned my audio folder.   nothing seems to work.  I really want to add another buss...

a while back i posted a similar help plea for apphang error msgs.  i wrote in to cakewalk support and they point to the plugs... well, i want to use these darned plugs.. why can't this problem with plugs work out already ?

in this case, the only plug outside of those included with X1 are my UAD plugs - and in this project, i am using only two instances...  i have more in use in other projects..  what gives ????????????