Deductions & credits

It is now April 18 (I filed for an extension), and it still won't let me e-file, though tables of what is working say it should work.  I recouped most of my foreign tax credits a few years ago, and in fact, the final carryover total is correct.  However, in 2017 & 2018 I used up my carryover, so that doing a "linear" sum for those two individual lines produced a negative number which TurboTax says is not possible (technically true, since it should be calculating the running carryover).  This bug is preventing me from e-filing.  Help!

 

Problem is that TurboTax is complaining about the worksheet and not letting me file, though it produces the correct Form 1116 and Form 1116 Schedule B for regular filing!