I found one:
2 3 6 5 9 8 4 for A-G respectively.
Strategy:
I got a bit lucky. I set A=2 and F and G equal to 6 and 3, and then 8 and 4, so that they would cancel out and I basically had a simpler problem to solve. From there it was some simple guess and check-an-check to get the inner expression to equal 102.