Chain ring hitting frame

I had to crimp the drive side chainstay further than it was ......
I must confess that I don't know what this means. (The frame is cro-moly by the way).

yes, if you run a really narrow 102mm BB with something design for 111mm

I haven't measured it yet, but it does look very narrow. That probably explains it then.
Been reading what Sheldon Brown has to say about bottom brackets/cranks (http://www.sheldonbrown.com/bbsize.html). I'm planning to bust out the vernier calipers tonight (yes, he can work them, my years teaching university physics students how to use them will stand me in good stead here), and see what my required chainline is.
If I understand correctly, by measuring the current spindle length, and the front chainline I get with the different cranks I have, I should be able to work out what length BB will work with which crank to give the required chainline (assuming the bugger doesn't bang off the chainstay).
thanks for enlightening me on the esoteric world of bottom bracket/crank compatabilities.