You need to be a bit more precise when taking a chain line measurement. It is easy though. Use calipers to measure the the diameter of the seat tube (or down tube). Divide that number by 2 and record the result. Then measure from the TIP of a chain ring tooth to the outer edge of the seat tube. Record the result. Then add the two numbers together. You want the front ring and the rear cog to be as equal distance from center as possible. Since rear cogs are pretty much stuck at ~42mms from center, adjusting the front chain ring to match is what's necessary.

So....take that front measurement and see how far inward you'd need to move the chain ring to get it to 42mms. Also, measure the current gap between the chain ring and the stay. Do you have enough room between the stay and the chain ring to move the crank inward the required amount? Let us know.

There are some frame and crank combinations that just wont work. If that is the case for you, one possible solution is to run a smaller chain ring to avoid contact with the stay. You'd then also need to change the rear cog in order to maintain the current ratio (if you like where it is).