Preprocessor error:

Hi, When I run the preporcessor, the pre.err gives me that error: "There is an error in BS and BE in w2_con.npt: The sum of BS-BE for all waterbodies does not equal NBR. Either illegal value or incorrect card somewhere in the following card 1976.87 1000.00 1000.00 3598.05 2170.07 4899.92 3934.94 1000.00 1000. 3283.42 2562.94 1000.00 1000.00 1425.61 1425.61 1000.00 1000.00 1347. 1000.00 1000.00 1388.60 1388.60 1000.00 1000.00 1236.14 1236.14 1000. ELWS" My model consists of 1 waterbody whit 9 branches, 49 segments and 17 layers. And I run the preprocessor a lot of time and it keeps failing between the segment length and water surface elevation portions of the bth.npt file. I suspect that my definition of the starting and ending branches for the waterbody is not correct. What is the exact definition of the starting and ending branches in the waterbody? Any help/suggestions would be appreciated. Thanks, Nicolas